DESIGNING *for humans

Ergonomics of Typography

While I've never had any formal education on typography (or perhaps, because of that absence), I've always had a great amount of respect and admiration for the discipline.  And just as a skilled driver can win a race without understanding the physics of internal combustion engines, the vast majority of us can write effectively without comprehending the physical details of the particular letters we are assembling.

But my interest in typography has recently grown due to my exposure to two leading practitioners.  Michael Beirut and Oded Ezer are very different kinds of designers.  Beirut, who I enjoyed seeing lecture a few weeks ago at a Philadelphia AIGA event, is an expert at applying typography to design projects.  His encyclopedic knowledge of type history can be seen in this video from Atlantic Magazine:

On the other hand, Oded Ezer is a true typographer who creates letter forms.  An Israeli, he works primarily in Hebrew type, both in applied and experimental forms.  I am currently reading Ezer's just-published The Typographer's Guide to the Galaxy, a visual review of Ezer's body of work ranging from relatively simple and direct treatments (like the image at the top of this post), to unconventional 3D treatments of letters and "Typospermatoids" (pictured below) - a hypothetical half sperm/half letter, "whose typographic information has been implanted into their DNA."  For more information, see Ezer's web site.

This emphasis and exposure to typography has caused me to re-evaluate my own perspective on the field.  For the usability or human factors practitioner, typography is generally considered in very functional terms.  Whether it's road signs on a highway, warning labels on medication or data captions in a software application, the focus is on the appropriate visual clarity, legibility and structural hierarchy.

But Ezer's unconventional, even anthropomorphic treatment of typography has me thinking of letters as actors with characteristics, rather than inert symbols.  More specifically, I realized that some of the basic principles of ergonomics could be mapped to typographical elements, and that typography and anthropometry (the study of human body measurements) are curiously related, at least metaphorically.

The fundamental principle of anthropometrics is that although people need to conduct the same types of behaviors and tasks, they vary greatly in their physical characteristics.  The same is true for different type faces - while they vary greatly in their physical characteristics and appearance, each must represent and allow the assembly of the same sets of characters into words.  That is, any font (English font, more specifically), is a variation on representing the 26 letters of the alphabet, etc.

But a more striking similarity between ergonomics and typography arises when one considers the rules that govern fit.  In my series on Ergonomics for Interaction Designers (part 3), I discuss the four key factors - reach, clearance, posture and strength.  These four inputs can be applied to assess the ergonomic fit of any person in any context.  But they are also metaphorically comparable for assessing the characteristics of a type:

• Reach can refer to the size of the typeface.  For example a taller type would have a greater "reach" or expanse than a condensed one.
• Clearance is physical space, or in the case of type, white-space.  A type with more space around the letters has greater clearance.
• Posture is the degree of alignment, such that a very slanted type would have a greater postural deviation than a a more linear type.
• Strength is the visible impact of the type as conveyed by the contrast of line thickness and boldness.

As a basic example, we can visually compare Arial Black with an italicized version of Times New Roman.  While both examples are at the same type size (13 pt), Arial Black clearly has greater reach and strength, while Times New Roman has a slanted posture.

Perhaps an interesting mental exercise, but anything more to it?  I've just begun to examine this interrelationship, but I think there may be inspiration here for typographers.  Gaining an understanding of human physical characteristics, and how they vary, could influence the design and application of typography, not for functional purposes as much as creative and exploratory endeavors.  Conversely, my interest in typography may lead to new ideas for addressing ergonomic issues - but if not, I will have gained a better understanding of an intriguing, ubiquitous design niche.`

Product Ergonomics in Metropolis

The March issue of Metropolis is focused on products, with the theme of Good Design.  And it contains several articles with a specific focus on ergonomics.  Niels Diffrient (illustrated above) presents what might be read as a self-contradicting design process, in The Real Driver.  On the one hand he posits a master-of-the-universe expertise as a best practice over contextual research:

"if you know what people do, how they do things, what their reactions are—and if you can measure all this—then you have a foundation reference for what they could use or want. You don’t have to go out and ask them, or track previous sales records, or determine what products are selling well."

On the other hand, the result of this approach is a chair that was "ten years in the making—I realized that people needed more comfort with less complication. By that, I mean fewer but­tons, levers—everything."  I recognize that I'm oversimplifying, but one wonders if the need for a less complex chair could have been identified with a few weeks of research rather than ten years of tinkering (although maybe getting it simple was all in the tinkering).

In the same issue Don Norman's Selective Memories, gives perspective on the evolution of design focus:

"If the last century was about rationality and reason (or attempted to be), let’s hope this one ushers in a deeper appreciation of human behavior. Ideally, logic and reason would remain important, but cognition (how we understand things) and emotion (how we value them) should play equally important roles."

Perhaps the fact that Niels and Norman - both well into their golden years - were the representation for ergonomics issues, speaks to the continued perception of human factors as the domain for gurus, while design is the realm of young rock stars?  But the content is is balanced by A Call to Arms, examining high-tech prosthetics for returning soldiers - "the ultimate ergonomic challenge."

Last, but not least, check out Ben Katchor's The Nozzle, a pseudo-nostalgic comic strip perspective on the role of customer research in design and marketing.

Ergonomics for Interaction Designers: Part 3

  

This is the third and final part of this introductory "mini-series".  Part 1 introduced the value of ergonomics to interaction designers, and Part 2 discussed some of the challenges and methods of anthropometric design for a broad range of users.  Now I am going to focus on how to identify ergonomic issues in observational and lab testing contexts.

Qualitative Observations Issues in Field Research

While interaction designers will typically lack special training in ergonomic assessment methods, most will have some degree of familiarity, if not significant experience with user-centered methods including contextual observation (aka ethnographic field research) and usability testing.  All of these methods share objective observation as a common data gathering method, and really only vary in the particular variables or characteristics that are the subject of study.  And while anthropometric data is intrinsically quantitative, qualitative observational research can be applied to identify ergonomic issues.  With these factors in mind, I've developed a basic set of ergonomic observational criteria to use as guidelines when evaluating design fit.  The guidelines are inspired by Stephen Pheasant's cardinal rules of anthropometrics, extended to qualitative field research. 

Pheasant advised focusing on Reach, Clearance, Posture and Strength.  I'll explain how these can be applied to a consumer electronics device, the InterAction Labs SQWEEZE Game Controller, pictured above.  The SQWEEZE is an accessory to the Nintendo Wii - inserting a Wii controller into the SQWEEZE unit allows the user to apply push/pull forces for gaming - think of drawing a bow string to shoot an arrow, for example.  While the SQWEEZE was well designed by ergonomics standards, it makes for a good example for explaining the four anthropometric characteristics:

• Reach typically refers to extending the arms and finger for effective control without over-extension.  In the case of the airport Kiosk discussed in Parts 1 & 2 there's a clear potential for placing the touch screen at a height or distance that would be difficult for some people to access effectively.  That type of reach is a non-issue for handheld devices like the SQWEEZE, but other types of reach can come into play.  In the case of two-handed devices, the distance between the handles needs to be appropriately set to accommodate a comfortable grip.  For the SQWEEZE, this distance actually varied between the push and pull positions as the handles flexed inward and outward respectively.  Similarly, the diameter of the handles affects the user's ability to adequately wrap his or her fingers around them; a smaller-scale, but just as important, reach issue. 
• While reach is about making sure things are not too far away, clearance is primarily focused on making sure things aren't too close together.  In interaction design terms, we might think of this as literal "white space".    There needs to be adequate room for the hands to move around the handles without bumping into anything, constraining usability or performance.
• We tend to think of posture as a full-body issue; standing upright or bending.  But in fact posture, defined as deviation from a natural, comfortable position, can be examined at the level of a specific limb or limb-segment.  In handheld controllers, wrist posture is frequently the factor of interest.  A design that forces the joints into contorted, unconformable positions, particularly for extended periods, is an ergonomic failure.
• Strength was particularly important for the SQWEEZE as it's essentially a force transfer device.  Testing with children indicated the device should not exceed 2.5lbs, but it also had to withstand up to 150lbs of crushing and pulling - the strength of a 90th percentile male.  In more general terms, designs should avoid requiring significant exertion by the user, but need to have sufficient resistance to provide feedback and avoid accidental triggering, for example as on a mobile phone keypad.

I've just scratched the surface of these four key ergonomic factors, but I want to re-enforce a couple of critical issues to keep in mind.  First, when we talk about an particular factor, it's important to consider it at multiple levels of scale.  In the case of posture, we might look broadly at how someone approaches a kiosk from an overall body perspective, but then focus more narrowly on the deviation of the hands and fingers.  Second, these factors are not independent of each other - in fact they are highly co-influential.  For example, if there is limited visual access, then a user may change his or her body and limb postures to accommodate improved field-of-view, but in doing so, increase the extent of reach and reduce the effective  transfer strength.

Last, but not least, I add a fifth factor which goes beyond the physical, to the perceptual and cognitive: Feedback.  Feedback refers to the user's ability to receive input on the impact of their actions on the interface or system.  For the SQWEEZE this can mean the tactile, visual and even audible mechanical feedback that corresponds with using the device.  For a touch screen kiosk, there is the perceived resistance of the touch service, and the feedback from the software responses.

Putting all this together, a person conducting observational research can use these five factors as a checklist for identifying potential ergonomic problems in real-time, or post-hoc (e.g. with video review). 

As a mnemonic aid, putting Feedback together with the other four ergonomic factors (Reach, Clearance, Posture and Strength), gives us FRCPS, or FoRCePS.  This was actually created as a mental cue during surgical observations, thus the clinical abbreviations.  I'm certainly open to more approachable re-combinations of the letters.

Measured vs Perceived Fit

In more formal assessment situations, such as usability testing, there are a number of quantitative methods for measuring fit and identifying ergonomic problems or risks.  But what seems well-designed on paper doesn't always result in well-received or usable.  I've observed numerous situations where the "technical" ergonomic requirements of a design would suggest a good fit, but in reality, the majority of users preferred an alternative.  There are various reasons for this ranging from individual differences, to preference for the familiar, to the influence of aesthetic design.  It's not the reason for these outcomes that matters so much as the need to capture this input.  In other words, it's just as important to measure subjective or perceived fit and comfort, as it is to measure anthropometric fidelity.

Recently, a number of surveys and guidelines have become available for measuring perceived comfort (I realized perceived comfort is redundant, but I'm including it for clarity).  For example, Kuijt-Evers, Vink & De Looze present a basic survey for hand tool comfort that covers factors from ease of use, to performance to....blisters.  In practice, it's helpful to use a vetted survey like this as a starting point, and then add and subtract questions based on the particular needs of your product, users and tasks, paying attention to the FoRCePS issues described above.  As with any user-research study, piloting and iterating the usability testing approach is as important as iterating the design itself.

 

 

Part 3 Takeaways

• Keep awareness of key ergonomic issues during design, research and usability testing by focusing on the five critical aspects of ergonomics - feedback, reach, clearance, posture and strength - keeping in mind that not all are of equal relevance for each design case.
• Good technical fit of a product is meaningless if users don't find it comfortable.  Therefore, evaluate the qualitative aspects of ergonomics in parallel with technical measurement.

Hopefully, these guidelines can serve as a starting point for thinking about and integrating ergonomics into your design process.  They can be readily included into existing design research and usability testing protocols There may be an intimidation factor, as there is a tremendous amount of technical knowledge in the ergonomics field (even a professional certification), but these qualitative methods can give you a high-level head start.  Remember, good design is as much as about identifying problems as solving them. 

Ergonomics for Interaction Designers: Part 2

Part 1 of E *IxD set up the conceptual background on why ergonomics is a valuable knowledge area for interaction designers and  discussed some of the basics of anthropometrics (designing for fit).  We were looking at Eye Height as a critical attribute for positioning the height of a kiosk display, so that a broad range of users could comfortably view the screen.  But having the display at an appropriate height for visibility is just addressing one aspect of interaction - the user also needs to control the interface - in this case via a touch screen. 

Designing for Multiple Anthropometric Dimensions

There are several body measurements that could be relevant for reaching a touch screen, but a practical one would be Forward Grip Reach distance - roughly the distance from the shoulder axis to the palm of the hand.  With those two metrics in mind - eye height and forward grip reach - you could picture any user as the function of two perpendicular lines  - a vertical line, representing the individual's eye height, and a horizontal line representing arm reach.  This is illustrated above for a range of three different users - note that the wheelchair user has a sitting eye height compared with the two standing users. 

While it might seem relatively straightforward as to how to situate the kiosk- place the screen at a distance and height that accommodates the greatest range of users - the story gets more complicated, because, well people are complicated. Not just complicated in a psychological sense, but in an anthropometrical sense as well.  The factor that adds complexity is the lack of correlation among anthropometric measurements within people.  What do I mean by that?  Let's take a step back and think in interaction design terms.

In interface design, one is typically working within the constraints of a display.  For example, a common resolution for web browsers is 1024 pixels x 768 pixels.  Some older displays might be set at 800x600.  So while the specific vertical and horizontal dimensions change, the relationship between height and width, or aspect ratio, remains constant at approximate;y 1.3 in both cases.  So if you're taking a design originally intended for 1024x768 and then need to scale it down to 800x600, it will need to be reduced proportionally. 

Ergonomic design would be much easier if people had consistent "aspect ratios", but our body measurements are not predictably proportional or strongly correlated.  Meaning the that all of the the tallest people in one dimension (such as eye height) do not always have the longest measurement for all other dimensions (for example, forward grip reach).  An extreme example, swimmer Michael Phelps has a reach that is longer than the majority of people of the same height.   What this means is that for practical purposes, each anthropometric variable could be considered independent of others. (Note that the level of correlation among different metrics can vary - for example, different attributes of the hand are closely correlated to each other, but measurements of different limbs are weakly associated.)  So when we are setting an eye height that accommodates the lower 5% to upper 95% of that metric, and then a forward grip reachthat accommodates the lower 5% to upper 95% for that particular metric, we are actually talking about two different groups of people.  Only a subset of people who fall within the eye height range will also fall within the reach range, albeit a large subset, but below the 90% of the population we are striving to include.

 

Another way of understanding this is described in the Herman Miller monograph on The Anthropometrics of Fit.  The design focus in this case is fitting people to a chair rather than a touch screen kiosk, but the concept is the same.  In the illustration above the back row represents all of the people who were the original intended audience for fitting a chair.  Each row in front  of that shows how a small percentage of people are excluded with each anthropometric variable (seat height, seat depth, etc.).  The front row shows the overlap of all four variables such that  "almost one-third of our sample [in blue] had at least one dimension out of four that was either smaller that the 5th percentile female or larger than the 95th percentile male."

Practical Solutions

There are some analytical methods for more effectively addressing these issues mathematically, but that's beyond the scope of discussion (for those interested, see Guidelines for Using Anthropometric Data in Product Design) .  In practical terms there are three solution approaches: design multiple sizes, adjustability and satisficing. 

Multiple sizes, as it implies, creates a range of models, where each is targeted at a specific subset of the user population.  The most extreme example of this (aside from bespoke, individualized designs) comes from clothing and footwear, where there are literally dozens of sizes and variations to enable a relatively close fit for the vast majority of the population.  For products such as furniture, this may be limited to three or four sizes, better known as small, medium and large.  In fact, this was Herman Miller's solution to the chair fit problem - creating three different sizes allowed for fit of 95% of the population between the smallest 1st percent and highest 99 percent - a greater range then they had originally intended. During the design of the airport kiosk that we discussed in part 1, one of the early proposed solutions was to create a two-sided kiosk with a "low" and "high" screen positions that could comfortably suit a wide range of users.

Adjustability is really a special case of multiple sizes where the user (or an expert) modifies the fit at installation or during use.  Most of us are familiar with adjusting the driver's seat in a car.  These seats are not infinitely adjustable, but typically have three or more control points that can lead to a very wide range of positions, within the available space constraints.  The downsides of adjustability are cost, reliability, and the extra work placed on the user to adjust the fit.  Note, that many users may not always set the best fit for themselves.

Satisficing,  is coming up with a single solution that fits the broadest range of users.  In practice this tends to skew towards the smaller or shorter end of users because, larger users can always bend (although at 6' 4" I can say that's not always comfortable) and smaller users may have physical limitations due to age or disability that take priority (legal and otherwise).  Most designs for public spaces will take this approach, as in elevators, water fountains and ATMs.   For the kiosk, the best single solution is pictured below at a fixed height and distance that was manageable for a broad range of users:

 

Prototyping for Fit

Whether designing a single solution or multiple sizes, it is important to  to follow a user-centered design process.  There may be room in interface design for "genius-centered design", but there's no substitute for real-world measurement of physical fit.  As in interaction design, prototyping can take many forms, depending on your goals and need for fidelity at each stage of the design process.  For example, if the initial goal was simply to conduct a real-world test of key dimensions, then a simple sticker on a wall could serve as a "prototype" for display position.  For more detailed issues, such as task-specific grips on a tool handle, foam mock-ups can be created and evaluated.

A typical UCD process for ergonomic fit would follow these steps, presented in an abbreviated form here:

1. Define relevant populations (e.g. age range, nationality, sex)
2. Define key dimensions or variable for fit consideration (e.g. height, reach, weight, etc)
3. Determine boundary measures for each anthropometric dimension from reference data, from lower 5th to upper 95th percentile (keeping in mind that some dimensions, such as head clearance in a doorway, may be one-sided)
4. Compare referenced dimensions with existing real-world products for reality check
5. Apply dimensions to create mock-ups for initial, informal ergonomic feedback with users
6. Refine design(s) to create foam or similar low-fidelity mock-ups for fit evaluation
7. Continue to refine as needed/budgeted

In part 3 I'll get into specifics around actually measuring the "usability of fit", that is, the quantitative and qualitative measures to assess whether a design actually fits a range of users.

Part 2 Takeaways:

• Anthropometric variables such as height and reach should be considered as independent of each other.  Therefore the more variables that you are designing for, the smaller that population that will fit across all of those dimensions. 
• Human bodies do not have fixed aspect ratios like screens do, but it seems a little more than coincidental that widescreen displays became popular in synch with the growth in population obesity.
• Providing multiple sized designs or adjustability are pragmatic solutions when good fit is important, but in most cases, a single, satisficing solution is required.
• Use anthropometric data as a starting point to build mock-ups or prototypes, then evaluate fit - more to be discussed next time.

Ergonomics for Interaction Designers: Part 1

Firstly, this is not about adjusting your chair so that you're not slumped over the screen when working on a Flash prototype (although office ergonomics is a very important subject).  Rather, the topic of discussion is the increasing value of ergonomics knowledge to the interaction designer.  Ergonomics is necessary for 3-dimensional, tangible product design where issues of physical fit and comfort are critical.  But for interaction designers in the 2-dimensional world of the display screen, ergonomics has largely been...irrelevant.  For example in most cases, interfaces are designed for existing, defined hardware that are out of the control of the interaction designer.  But things are changing...

Driving Factors
The continuing convergence of digital interfaces with physical products is putting interaction designers in a position where knowledge of anthropometrics, kinesthetics, and other non-cognitive human capabilities is valuable for creating effective design solutions. 

There are several trends contributing to this, including:

1. The rapid proliferation of touch screen and other gestural interfaces which combine "direct" physical control with digital interface design.  If you want to design for a finger, you have to know how a finger works. 
2. The growth of ubiquitous computing leading to an increased range of scale and form factor in devices that contain interfaces, from traditional computers and laptops, to kiosks, tablets, phones, interactive video walls, electronic ink and consumer appliances (to name a few).  As a result, people are interacting with interfaces in  range of positions and contexts that go beyond simply standing or sitting in front of a screen. So beyond fingertips, knowing how people can reasonably user their bodies to hold, view, reach and interact is valuable.
3. Computing power and bandwidth across such devices now supports more complex, involved tasks such as data entry, long duration reading and gaming, all of which can lead to risks for repetitive motion injuries, or at least discomfort. Having a knowledge of the types of interactions that can cause such injuries, and how to design around them, is essential.
4. An ever increasingly diverse range of end-users are gaining access to interactive devices, across age, and physical characteristics.  For example, the One Laptop Per Child campaign has produced a global, kid-sized laptop.  In home health care, a market of predominately elderly users, more devices contain embedded interfaces.  And ADA and similar legislation requires that devices are accessible to users with a range of disabilities.  In other words, you need to know your user, for it is not you - a given in interface design, a necessity in ergonomic design.
5. Last, but not least - interest.  Several of the factors described above are driving many interaction designers to explore and study the world of physical product design. For example, the IIT Institute of Design is hosting a "thinkering" workshop specifically to provide "an opportunity for interaction designers to get their hands dirty with electronics, soldering, and wiring, and learn how to interface hardware artifacts with virtual interactions."  Just as it is important to understand the electro-mechanics of hardware, it is essential to understand the relevant mechanical attributes for the users of such hardware.

What all of these trends have in common is a growing need to accommodate human physical characteristics and constraints in the design of digital interfaces.  For the most part, this skill set is not part of the experience of interaction designers.  Consequently, I'm posting this first in a series of explorations on the topic of Ergonomics for Interaction Designers, or E *IxD for short.

Anthropometrics: The Building Blocks of Ergonomic Design

In any field of design there are those elements that are defined and unchangeable, and those that are malleable  It is the latter in which designers specialize.  For example, in interaction design, the fixed elements might include a specified screen resolution, development language and minimum type size.  As you might guess, in physical product design, there are many constraints, but human physical characteristics are the most fundamental.  Therefore, the most fundamental design question is, how do I design for the range of human physical constraints?  For this, we turn to anthropometrics the measure of human body size and proportions. 

Let's focus on one simple anthropometric variable - height.  Actually, even height is not that straightforward as there are many types of height: stature (what we mean when we say height), eye height (distance from the ground to the eyes - important for display positioning), shoulder height, fingertip height (standing, with arms relaxed), and sitting elbow height, to name a few. 

Suppose we are designing an interactive touch screen kiosk that will be used in an international airport terminal (like the one pictured below, via Core77).  It is expected that the kiosk users will include travelers from around the world, male and female, from kids through elderly adults.  While this may sound like the worst case scenario for physical design (and it is), it's also very typical.  In this case we are going to focus initially on eye height because we want to set the display so that it can be viewed most easily without looking up or bending down too much.  (Note that line of sight is optimally about 10 degrees below the horizontal plane.)

If we refer to anthropometric data tables, like those found in Stephen Pheasant's Bodyspace,  we find quite a range in eye height, varying by nationality, age and sex.  For example an average, 50th percentile Dutch man has an eye height of 1670mm, while an average, 50th percentile eight year old British girl has an eye height of 1165mm.  That's over a 500mm difference, and those aren't even the most disparate populations!  So how do we accommodate the diversity of physical characteristics?

Molenbroek and de Bruin discuss the various approaches that one can take to accommodating the range of anthropometric characteristics, summarized in the diagram below:

The most basic approach, if we can even call it that, is "Procrustus", which means that no attempt to accommodate the user has been made, and the user must adapt to the product, however it happened to be designed.   Incidentally, this term comes from Greek Mythology, where Procrustes was fitted to a bed by sawing off his head and feet.  Only slightly better is the Ego-design approach, where the designer uses his or her own body as a reference.  Now every designer does this to some extent for convenience, but it should serve only as a starting reference point.

Design for the mean sounds like a good idea - find the average eye height, and the majority of users will be accommodated.  False assumption - as the diagram indicates, a majority of people are excluded by relying on the mean, with only a few falling into the sweet spot in the center.

Designing for one end of the spectrum (small) or the other (tall), can work in some cases.  For example, if you design a door to accommodate the tallest users, then by definition, those of shorter stature will fit as well, as clearance is a one-ended variable.  But in our case, the appropriate height of a kiosk display is a two-ended issue - there is a hypothetical "too high" as well as a "too low".

Which brings us to some workable approaches.  Design for adjustability means that the product can accommodate a range of users, typically through a mechanical solution. For example, a tilting, height adjustable screen, or multiple interaction stations set at different eye heights.  Of course adjustability in the physical world adds cost and complexity, and can lead to unreliable products, so is not always an available solution. 

In the end, the most common solution is to Design for More Types.  In practice this typically means defining a population and then fitting for a reasonable range within that population. Traditionally that range spans from the smallest fifth percentile to the largest 95th percentile.  This includes a very broad range of users, but purposely excludes the most extreme 10% of the population (the largest 5% and smallest 5%) - the long tail, where a small number of outlier users can account for a significant design change. 

Last, but not least is the ideal - Design for All.  This means that the product can fit the entire range of an anthropometric characteristic.  This is technically possible as humans are not infinitely variable in any dimension.

Part 1 Takeaways:

• Knowledge of ergonomic methods and techniques is becoming a valuable skill set for interaction designers due the growing diversity of devices, users and contexts for interaction.
• Anthropometrics, the measure of the human body, is a fundamental area in ergonomics, and a starting point for understanding how to design systems that fit people.
• Among anthropometric approaches, designing for a broad range (5th to 95th percentile) is often the most practical and accomodating.
• When furniture shopping in Ancient Greece, be specific about measurements.

In Part 2 I'll discuss how to apply the anthropometrics to a real-world interaction design problem, and also discuss the added complexity of dealing with multiple anthropometric variables - like eye height and arm length, so the user can actually see and reach the screen.

comments and suggestions always welcomed...

Ergonomic Innovations at CES

I'm trying to track the hundreds of new product announcements at this year's Consumer Electronics Show.  And while there's always innovations in technical functionality, it's hard to spot a direct ergonomic improvement. 

But here's a couple of exceptions to that rule:

• The Samsung HMX-R10 video camera(pictured above).  A CNET previewer said that it features a "lens that's angled at 25 degrees so you can grip the camera more naturally in front of you for both photos and video--or at least that's what I'm hoping for."
• The Kodak Z980 digital SLR camera  has two shutter buttons.  One in the traditional top right, and the other on the side of the body for taking pictures in portrait mode ((see video below).  In other words when you hold the camera sideways, you have a more accessible and natural reach to the secondary shutter button.

Ergonomists Without Borders

I think there's a real opportunity for ergonomic expertise to support many of the international programs that support developing communities.  For example, Engineers Without Borders enables the "implementation of sustainable engineering projects, while involving and training internationally responsible engineers and engineering students."  These projects are frequently focused on basic human needs such as water purification/delivery and sanitation.  Many of these solutions require human power.  I wonder whether ergonomic expertise has been applied to the design and implementation of these systems.  This is particularly important, given the diversity of anthropometric characteristics across the served communities.

One organization that is contributing is Synergo Arts, which is a "resource for ergonomics education, consulting, and design for communities of artists and artisans around the  world, to maximize their health, income, performance, productivity, and the quality of the art or craft that they create."  Their ergonomically designed weaving bench (pictured above) also won a User-Centered Design Award from the Human Factors & Ergonomics Society in 2007.  The bench is actually produced by local carpenters (in South America) for local weavers, thereby benefiting two industries.

If you know of similar organizations or individuals working towards improving ergonomics in developing communities, please contact me.

"Green" Ergonomics in LEED Building Design

 

Several months ago I discussed the relevance of user-centered design to the successful design of sustainable products and services.  Now a more concrete (literally) example of the intrinsic connection between human factors and green design.  

Alan Hedge writes about The Sprouting of "Green" Ergonomics (PDF) in the December issue of the HF&ES Bulletin.  Hedge reports on the new version of the U.S. Green Building Council's LEED Green Building Rating System, which includes specific guidelines and credits for creating an ergonomic environment.

The guidelines focus primarily on office workstation ergonomics (although industrial settings are touched on as well).  For example, the LEED guidlines cover standards around display adjustability and glare, work surface dimensions, and chair adjustability.  You can download relevant "green" ergonomic checklists from Cornell's ergonomic resource.

Adding ergonomics to LEED requirements seems like a natural extension to me - both are targeted at improving the health and comfort of individuals who work within buildings.  There may also be some direct correlations between the more traditional LEED categories such as materials & resources, and ergonomics. For instance, a poorly fitted workstation may be more readily replaced than one chosen appropriately - thereby leading to increased materials use.

Hedge also makes the point that the new LEED guidelines will change perceptions about office ergonomics - from a reactive, problem-solving model in most cases, to a proactive problem-avoiding approach as it is intended.

 

State of the Art - Ergonomics of Chairs

In an intriguing coincidence, two top-names in ergonomic-focused industrial design have introduced new chairs that take different approaches to fit and comfort.  As with my recent discussion on handle design, chairs are another iconic challenge to ergonomic designers - thousands of versions, but no exact set of rules to achieve perfect fit and comfort.

Core77 posted a "living with" review of the Herman Miller Embody chair.  In other words, they actually "spent every day for just over a month living with the chair, putting it through its paces, and trying to wear it out."  I encourage you to read the full review of this innovative chair, but from an ergonomics perspective I was most interested in how the chair reacted with the user:

"The designers apparently intended this chair to encourage you to move around in it, and there's a five-page PDF detailing how the chair was designed to promote "tissue perfusion"..in other office chairs I've used, I will of course occasionally stretch; but the difference with the Embody was that I was stretching into the chair, using parts of it like some kind of Pilates ball. It really has to be experienced to be understood."

A simpler alternative is the the eponymous Diffrient Work Chair for Humanscale, reviewed by ID Magazine's editor-in-chief Julie Lasky,   Diffrient has been working on the chair for a decade, so that

"The user’s weight automatically transfers a proportionate force for recline, eliminating the need for adjustment and the usual spring mechanism; leaning back ramps the seat upward and forward to achieve the appropriate upright or reclined position...Though he considered a forward tilt mechanism in early Diffrient chair prototypes, he chose not to have one in the end because of the added cost and complexity. Besides, he says, the “mechanism encourages the common but undesirable position of people straining to operate the computer.”

While these two chairs differ in their ergonomic approach - the Diffirient chair is expected to cost less than half of the Embody - they are designed with different functions and towards different uses - so a direct comparison is not necessarily relevant.  But as a researcher focused on both quantitative fit and qualitative comfort, I am looking forward to experiencing the state of the art from two of the most respected design names in the industry.

Top Posts of 2008: DfH Year in Review

With just a few weeks left in the year (and even less productive blogging time), I thought I would put together this brief "best of 2008" on Designing for Humans.  If you're new to the blog, this is a good way to catch-up on some of the highlights you may have missed over the past year:

• User Research Technology - Always a core theme on DfH, this year I took a hands-on look at applying many emerging tools to support design research.  This included the Livescribe Pulse Pen, Casio's High Speed Camera and the IDEA award winning Size China anthropometric data set.  Looking to the future, I unveiled the FieldCREW workstation concept (pictured), and discussed the state of user research technology at the Design Research Conference.  Still waiting on the FitBit tracking device (hopefully in the approaching weeks).
• Reading - I recommend the best book on user research, a forthcoming book on product design, design research-related articles in the Harvard Business Review, human factors in mechanical engineering and an international standard on product usability that's not worth the money. 
• Awards - I blogged on the unique experience of judging both the IDEA awards and the ID Magazine Annual Design Review in the same year.  Also, read about the IDEA award winners in the research category.
• Ergonomics- I put together the FoRCePS guidelines for observing ergonomic problems during contextual observation.

...okay, my link pen ran out.

Designing the Perfect Grip - Of Handles and Homepages

The handle of a tool or product is a lot like the home page of a web site - they are both the user's primary touch point, allow access to the available functionality, and significantly influence how the overall product or site is perceived. 

Another important similarity is that even though thousands of handles and home pages have been designed, there is always a challenge when creating a new one.  This is understandable for home pages as there is so much variability in terms of content, information architecture and interaction design options.  But it's surprising for handles, as they have been around (in both natural and man-made forms) for thousands of years - you would think we would have gotten it right by now.

In fact there are recognized guidelines for handle design - for example NIOSH's guide for hand tools includes recommendations on handle diameter, grip span, etc.  But there is also great variability in handle design depending on the user population's range of physical characteristics, the particular task context (e.g. wearing gloves) and the product materials, to name a few.  So any guidelines are going to be a compromise across a set of these characteristics.  And note these metrics tend to focus on anthropometric fit, which does not always correlate directly with the user's perceived comfort.

It's important to keep up with changes in data and guidelines.  One of the key dimensions in handle design is circumference.  The NIOSH guide suggest a range of 1.25 to 2 inches (about 31.75 to 50.8mm).  A new study published in the October issue of Human Factors has looked at this issue in more detail.  Investigation of Grip Force, Normal Force, Contact Area, Hand Size and Handle Size for Cylindrical Handles is the very descriptively worded title.  They take a detailed look at the how and why of finger anthropometrics and geometry impacting effective grip:

"For a small handle diameter,finger flexion results in skin folding and reduced contact with a handle.  For a large handle diameter, the handle surface may not fit into the curvature of the finger because gripping flexes the fingertip."

At the end of the article, a rare find - a specific numeric recommendation is given: "the mean optimal handle diameter can be calculated to be 40mm". 

Now before you go designing all handles with a 40mm diameter, keep in mind that this is optimized around a simple cylindrical handle - and its based off of US Air Force hand measurement data from 1971.  Like all anthropometric guidelines, take with a grain of salt - use it as a starting point, but build rough models to evaluate fit with an appropriate range of representative users.  In other words, the same user-centered design process that you would use to create any artifact - like a web site home page.

"There is No Angle on the Human Body that was Designed for a Collision"

Acura is running an elegant new TV ad highlighting vehicle safety.  It shows human bodies in motion as if they were in collisions, but out of the context of an automobile. 

Not to be taken too literally, but I might disagree that "there is no angle on the human body that was designed for a collision" - case in point, the orbit that protects the eye -

"The bony structures of the orbit protrude beyond the surface of the eye. They protect the eye while allowing it to move freely in a wide arc." (Merck Manual)

Size China Headforms & Data Now Available

I've been talking about SizeChina ever since I heard Roger Ball present at the 2007 IDSA conference.  Subsequently, his effort to create reference anthropometric data of Chinese heads and faces for product designers has won an  IDEA Gold award for research. The project made valuable discoveries regarding key differences between Asian and Caucasian head sizes and ratios, that have not been consistently accommodated in the design of eyewear, protective headgear, medical/dental products, etc.

Finally, the products from the SizeChina project are commercially available from Certiform.  These include a set of 10 representative solid headforms (pictured).  You can purchase the set for $20k or a single on for $2500.

The detailed data sets (3D scan files and measurements) are also available at various prices/package levels, ranging from a 12-person "light version" for $399 up to almost $15k for the complete data set of over 1500 scans.

Certiform has provided a sample file set in Excel format to give you a sense of the level of detail included: Download Landmarks_data_sample.  See the diagram below to interpret the data set, especially if you can't tell your tragion from your zygofrontale.

Comfort in Using Hand Tools

A recent dissertation out of Delft University (Netherlands), discusses Comfort in using hand tools: theory, design and evaluation.  You can download the document as a PDF (note - cover page is in Dutch, but document is written in English).

Kuijt-Evers covers the state of the art in measuring ergonomic comfort for non-powered hand tools and conducted empirical research to validate a set of qualitative comfort predictor for use in design and evaluation.

Here's the abstract:

Everyone uses hand tools in their daily life, like knife and fork. Moreover, many people use hand tools in their profession as well as during leisure time. It is important that they can work with hand tools that provide comfort. Until now, the avoidance of discomfort was emphasized during the design process of hand tools, like screwdrivers, hand saws and paint brushes. In the near future, the focus will shift towards providing comfort. However, some questions need to be answered to make this shift, like: What does the end-user mean with comfort in using hand tools? How can we translate this into hand tool design and the design process? How can we evaluate hand tools on comfort? These questions are answered in the current thesis.

Bryce Rutter on The Soul of Ergonomics

Metaphase's Bryce Rutter, IDSA is prepping to deliver the next session of the Designer Spotlight series. His presentation, titled The Soul of Innovation will reveal how ergonomics can be made sexy. Join us for an online presentation on May 21 at 1 pm EST as he shares case studies and offers how-to tips. To register, call Donna at 703.707.6000 X 100 or visit: https://sslserver.com/idsa.org/absolutefp/designer_spotlight_2008.html

[From IDSA DesignBytes]

Ergonomics, the Elderly and Elevators

A couple of interesting articles related to design and ergonomics in the past week:

-Businessweek had a blurb on Nissan's efforts to design cars for the elderly by wearing a restricting body suit (see image).  Although Bw was not the first one to report on this, and in fact other designers have previously developed similar simulation techniques, I really liked this illustration.  See, "How to Drive Like and Old Guy"  fourth image in slideshow. 

-In an unrelated piece, The New Yorker magazine featured an article "Up and Then Down: The lives of elevators",  While intrinsically interesting to anyone who rides elevators, ergonomists and designers will find the discussion of "proxemics" particularly fascinating from both psychological and anthropometric perspectives:

"Bodies need to fit. Designers of public spaces have devised a maximum average unit size—that is, they’ve figured out how much space a person takes up, and how little of it he or she can abide. The master fitter is John J. Fruin, the author of “Pedestrian Planning and Design,” which was published in 1971 and reprinted, in 1987, by Elevator World, the publisher of the leading industry magazine, Elevator World. (Its January issue came with 3-D glasses, for viewing its best-new-elevator-of-the-year layout, of the Dexia BIL Banking Center, in Luxembourg.) Fruin introduced the concept of the “body ellipse,” a bird’s-eye graphic representation of an individual’s personal space. It’s essentially a shoulder-width oval with a head in the middle. He employed a standard set of near-maximum human dimensions: twenty-four inches wide (at the shoulders) and eighteen inches deep. If you draw a tight oval around this figure, with a little bit of slack to account for body sway, clothing, and squeamishness, you get an area of 2.3 square feet, the body space that was used to determine the capacity of New York City subway cars and U.S. Army vehicles. Fruin defines an area of three square feet or less as the “touch zone”; seven square feet as the “no-touch zone”; and ten square feet as the “personal-comfort zone.” Edward Hall, who pioneered the study of proxemics, called the smallest range—less than eighteen inches between people—“intimate distance,” the point at which you can sense another person’s odor and temperature. As Fruin wrote, “Involuntary confrontation and contact at this distance is psychologically disturbing for many persons.”

Sizing China

Following up from my posting on the Size China presentation at last year's Connecting '07 IDSA national conference, Metropolis magazine has a feature article on Roger Ball's research effort to create a digital database of head anthropometrics for the Asian market. Sizing China

 discusses the inspiration and rationale of the project, its technical challenges ("Aside from chasing chickens out of the scanning room, the Size China team had to battle with time"), and the surprising findiings:

Ball had initially assumed there would be a correlation between head sizes and eye, nose, mouth, and ear sizes, which would allow him to create a series of facially featured average Chinese heads. After scanning several thousand subjects he discovered that there is no correlation between the zones of the face at all: “You could have a very large head, very tiny eyes, and a medium mouth, or a tiny head, very big eyes, and an average mouth,” he says.

With great photos, anecdotes, and a clear articulation of the benefits of this project, Metropolis achieved the near-impossible - making an anthropometric study an interesting subject.

[Note - I am beta testing some new formatting options on TypePad, so things may be a little quirky, over the next few posts]

High-Speed Photography and Video for Ergonomics

High-speed video and photography is getting a lot of attention these days.  This month's Wired Magazine  summarized the history of high-speed photography, from the work of Harold Edgerton to the recent use of lasers to capture images with shutter speeds of 300 x 10^-15 seconds!
(also see last year's article on The Ultimate High-Speed Photography Kit).

And just last week, Vision Research, makers of commercial-grade high-speed cameras, announced the Phantom V12 (inset photo), capable of recording one million pictures per second.

But from a practical point of view, the most intriguing news is the Casio Exilim Pro EX-F1. Due in March for an estimated $1000, this camera brings high-speed photography and video to the digital prosumer market.  Several unique features include:

• Ultra High Speed Burst Mode: Up to 60 shots at can be taken at once, so 60 shots per second for one second, or 5 shots per second for 12 seconds, are possible.
• High Speed digital movie recording of up to 1200 frames per second (fps)
• Full High Definition recording at standard speed

In addition to these impressive capabilities, the camera offers some novel user interaction feature such as a buffer to pre-record images prior to the shutter depression, allowing room for error when trying to capture a quick event; and Slow Motion View to review real-time events in slow-motion on the cameras LCD via a buffer.  And of course...stereo recording : )  All of these features are exciting from a gizmo geek's perspective - and there are plenty of reviews and videos from CES. 

But there's a tremendous opportunity to apply this technology to product design.  Specifically, I will be using the high speed burst mode and high speed digital movies to capture motion during rapid manual tasks  - such as the use of a construction tool, surgical instrument or mobile device keypad.  Extending visual perception to micro-seconds is likely to reveal interesting sub-patterns of movement and orientation that are overlooked or invisible at a standard time-scale.  Moreover, it introduces a new perspective on observing physical behavior that expands user research capabilities - at least as far as the presumably massive file storage and power needs of this unique camera will take you.

Download the Human Factors Design Standard

Even if you don't design aircraft, the Federal Aviation Administration's Human Factors Design Standard, is an invaluable (and free) reference for design practitioners. 

The complete design standard is large (10MB) and comprehensive - "an exhaustive compilation of human factors practices and principles" - but it provides succinct and tactical, evidence-based information.  For example, concerning touchscreens, fourteen specific guidelines are given for button size, labeling, position, dead space, etc, but the need to test with representative users is also recommended to keep these rules grounded in reality.

In 2007 the FAA added draft updates related to interface design, including displays and non-keyboard input devices (e.g. mouse, joystick, touchscreen). 

A brief, anonymous survey form is required to download the Human Factors Design Standard (HFDS).  Once past that, you may download the entire document or any of the 15 individual chapters or drafts, ranging from Alarms, Audio and Voice to Anthropometry and Biomechanics (a particularly strong section of the document).

Sparsely, but appropriately illustrated, the HFDS gives the actionable guidelines that so many product designers and students are desparate to find in a single location.

PS - Experimenting with larger font size for better readability on recent posts.

Ergonomics of Wheelchairs

...an interesting thread from Google Answers on design anthropometrics to accommodate people in wheelchairs.

Ergonomic Resources from/for Furniture Designers

Several office and furniture design companies provide free, valuable resources on ergonomics for design.  I've highlighted two particular examples:

• The ergonomics section of the Allsteel web site includes a downloadable reference guide: Ergonomics and Design (PDF).  This is one of the best introductory ergonomic guides that I've seen, with a clear explanation of basic anthropometrics and references for further information.  The guide effectively provides illustrations, a glossary and representative data tables to inform readers about designing for offices - including universal design.
• Steelcase's ergonomic section covers many of the same fundamentals, but give's broader consideration to other areas of ergonomics such as cognitive and acoustic concerns in office design.  The site also has a dedicated research article section, which covers both strategic (e.g. "A Macro-ergonomic Approach) and tactical (e.g. "Choosing a Chair") topics.

HF Highlights from Connecting '07 - Size China

Given the 140(!) sessions that took place at the 2007 IDSA national conference this year in San Francisco, there's no shame in missing a few sessions.  Of course the topics that you really want to see all occur simultaneously, leaving one with a "paradox of choices".   

I was most impressed by Roger Ball's Size China:  A New World of Ergonomics.  Roger is a designer by training and professor at Hong Kong Polytechnic.  For the last 18 months, he has been building a database of anthropometric data by digitally scanning over 2,000 Chinese citizens.  The project was inspired by the lack of a comprehensive anthropometric database of Asian head and facial features, comparable to what is available for Caucasian populations.  For example, most helmets used in China were designed against Caucasian measurements and are ill-fitting due to significant differences in head shape between Asians and Caucasians(see image).

Roger said that his data will be made available for free to academic endeavors by contacting him directly.

Learn more about the project at: http://www.sizechina.com/html/index.html

I was intrigued by this project and interested in potential differences in perceived and reported fit among populations, not due to head size, but due to potential cultural and linguistic variances in what is considered comfortable and fitting. Perhaps some of the presenations on measuring emotion would have helped me address those issues, but like I said, I couldn't make all of the presentations.

Updated Hand Anthropometric and Strength Data

These are updated links, rather than updated data per se:

Research conducted for by the British government's Department of Trade and Industry on strength factors across ages and nationalities.  Primarily focused on hand-related characteristics (e.g. grip, push-pull strength):

• Strength Data for Design Safety - Part 1
• Strength Data for Design Safety - Part 2
• Anthropometric and strength data for disabled

Extensive hand anthropometry data from U.S. Army study:

• http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=ADA244533&Location=U2&doc=GetTRDoc.pdf

Design for the Hand - Event

On Saturday May 13th the Hagley Museum and Library in Wilmington, Delaware (about 30 minutes from Philadelphia) will host "Design for the Hand", a seminar on ergonomics and design for the hand.

According to the IDSA Philly site:

"This event features presentations by Rachel Delphia of Carnegie Mellon and Carnegie Museum; Bryce Rutter, Ph.d. of Metaphase Design; and a design charette for attendees."

The event is scheduled from 11AM-3PM and  pre-registration for IDSA members can be done through  this form.

Body Dimensions of the Belgian Population

Very extensive, filterable data from research done in Belgium, includes detailed measurement data for multiple age groups and even wheelchair dimensions and guidelines.  This may be the most complete and up-to-date anthropometric data sets I've seen.

http://www.khlim.be/~rmotmans/Introduction.htm

Ergonomics Course Modules

The United States Air Force has a set of online course on ergonomics, including courses in:

• Tool Design
• Workstation Design
• Basic Biomechanics

This is quite useful information, and is not focused on military applications specifically.  For example, the section on Tool Design demonstrates different types of hand-grips with an ice-cream scooper.

"Extra-Ordinary" Ergonomics: How to Accommodate Small and Big Persons, The Disabled and Elderly, Expectant Mothers, and Children

A new reference book has been published, focused assessment and design of the Ergonomics of special populations.

From the Human Factors and Ergonomics Society description:

"Underscoring the need for extraordinary ergonomics, the book illustrates various approaches to measuring the characteristics, capabilities, and limitations of those who differ from the norm. Kroemer explains how to assess and determine abilities and needs and demonstrates how to design tools, homes, and environments to make working space safe and living space easy.

Researchers and students will find helpful information about measuring people's sizes, strengths, weaknesses, and capabilities, and from this information determine the needs for specific ergonomic accommodations. The book enables human factors professionals, architects, and designers to devise work tasks, devices, tools, and environments for special populations – particularly for children. Health care professionals and employers will discover ways to help people who suffer from temporary or permanent disabilities so they can cope with the demands at work, at home, or in a care facility."

Anthropometric Reference Data, United States, 1988-1994

I've located some more recent data sets for the U.S. population from the National Health and Nutrition Examination Survey of the Center for Disease Control (CDC).  This is an extensive data set, focusing on a range of characteristics, primarily around health/nutrition attributes, but certainly applicable to many ergonomic design characteristics.  Includes 64 tables covering everything from weight, height to wrist and buttock circumference:

Anthropometric Data Sets

Anthropometrics for Furniture Designers

The site "Value-Created Review" (Candian ejournal for contemporary furniture design) has a page dedicated to ergonomic information and resources.  It includes basic information and diagrams (pictured), links to other online resources and ergonomics books.

Strength Data

Research conducted for by the British government's Department of Trade and Industry on strength factors across ages and nationalities.  Primarily focused on hand-related characteristics (e.g. grip, push-pull strength).

Strength Data for Design Safety - Phase 1

Strength Data for Design Safety - Phase 2

Anthropometric Data Sources

One of the most common requests from the recent survey was for anthropometric data sources.  Unfortunately, most data sources are proprietary and/or costly. 

Here are some of the leading data and measurement providers:

Civilian American and European Surface Anthropometry Resource Project—CAESAR

PeopleSize

AnthroTech

Here are links to a few publicly available sources, but please comment if you know of more modern and diverse data sets that are available:

U.S. Military Anthropometric Data Sets

NASA Anthropometric Guidelines (based on American males and Japanese females, 2000)

Anthropometric Data of Children

UPDATE: The Human Factors and Ergonomics Society has recently published Guidelines for Using Anthropometric Data in Product Design that discusses methods, resources and practices for designing for the human body.