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Why Invest in a Usable User Interface? (Measuring the ROI for a Usable User Interface: Part 2)

(Read Part 1, “Where Do You Fall on the Usability Maturity Ladder? (Measuring the ROI for a Usable User Interface: Part 1)” for a look at which industries already recognize the value of a usable UI.)

Recently I realized that some companies, and even whole industries, still need to be convinced of the value of upfront user research and usability testing when developing a user interface.

In last week’s post, Where Do You Fall on the Usability Maturity Ladder? (Measuring the ROI for a Usable User Interface: Part 1), I reflected on organizations’ various motivations for trying to ensure the usability of the products they design, and I introduced my Usability Maturity Ladder.

At the bottom rung of that ladder are companies who consider usability to be a burden. They may understand the usefulness of a user-centered design process when it comes to engineering and form development, but they get by with user interfaces designed by software engineers. In the movie, Moonstruck, Cosmo (played by Vincent Gardenia) may as well have been persuading one of these companies to invest in a usable UI when he said, “It costs money. It costs money, because it saves money.”

Unfortunately we don’t all possess Cosmo’s succinct charm. So how do we begin to make the business case? In this post, I attempt to get back to the original question of why we should invest in user interface/interaction design.

Why Invest in a Usable User Interface?

As I mentioned in Part 1, there has been a great deal of research into the return on investment of good design processes in general (see Design Council, 2004 and Rae, 2013) and specifically on product usability (for an overview, see Bias & Mayhew, 2005). In summary, the benefits can roughly be divided into two categories — those that more directly affect the manufacturer, and those that primarily affect the consumer.

Manufacturers’ Concerns


1. Increased Product Sales

Before purchasing a product, consumers ascertain its ease of use by observation, hands-on use, or reading product reviews. Perceived ease of use can have a significant impact on purchasing decisions — especially for consumer products. This, in turn, impacts repeat sales and consumer reviews that can then drive additional sales.

If the UI is painful, a consumer will do everything not to use the brand again, including seeking out a different brand.

This is easy to see in the consumer space, where people may even wait in line to be the first to get a new product. But we’ve even encountered this attitude with commercial products. While conducting user research for medical device design, lab techs told us they remember and ask for the brand that is easiest to use and most consistent.

2. Reduced Return Rates

Even after purchase, poor usability can influence revenue due to product returns. Consumers often buy products to try them out and return them if they are not to their liking. This is less of a factor for larger products such as home appliances and industrial equipment that require a substantial investment in transportation, installation, and set-up — and are therefore investigated more rigorously before a purchase is made. However, the return policies at many retailers allow products to be returned for any reason after purchase if the consumer is not completely satisfied.

3. Increased Revenue from Supplies, Services, and Support Contracts

As with the proverbial razor/razor blade revenue model, many products today serve only as the on-ramp for the revenue stream. In these cases, simply selling (or even giving away) your products does not guarantee success. If you do not succeed in getting people to use your product, you will lose the revenue associated with supplies, services, and support contracts. Sometimes this can be difficult to quantify.

I once conducted a study to determine if better instructions would encourage people to send empty toner cartridges from an office printer back to the manufacturer. While we can all feel good about recycling, the manufacturer was most concerned that the used cartridges would end up in the hands of “toner phoners” — companies that refill cartridges and sell them at a discount, thereby robbing the original manufacturer of revenue from ongoing toner or ink sales.

4. Reduced Support and Help Line Costs

In the consumer space, it’s a strike if someone needs to pull out the user manual to figure out how to use a product. He or she may resort to calling the help line. This support is expensive. In companies with a significant install base, management keeps close tabs on this and can tell you the average cost per call — these costs may shock you.

5. Building the Brand

Usable user interfaces are an opportunity to create meaningful brand identities. As physical products “disappear” and digital interaction takes center stage, the UI becomes the primary medium for brand communication and an opportunity to connect more deeply with users. Companies work hard to build up a brand’s reputation. It can take years of relentless focus on quality and service.

A poor user experience caused by poor usability can squander a brand’s hard-earned reputation. On the other hand, a superior user experience can help build brand loyalty.

6. Better Product Reviews

Major consumer publications run weekly columns reviewing the usability of tech devices. Today, reviews of even sophisticated commercial devices are available online. Such reviews, positive or negative, can have a significant impact on consumers’ purchase decisions. One study found that 51% of millennials trust strangers’ online reviews more than they do recommendations from family and friends when deciding which product to buy.


Just like cement, a product is most easily modified early in the development process. The closer it gets to launch, the more it “hardens.”

7. Reduced Development Costs

Although it may seem counterintuitive, a good user-centered design process can actually reduce development costs. For example, correctly identifying user requirements early decreases the likelihood that redesign will be required later (Smith & Reinertsen, 1995). Detecting showstopper issues close to (or, God forbid, after) product launch can be incredibly costly. I use the analogy of hardening cement — a product is easily modified early in the development process, but closer to launch becomes much more difficult to change, and this holds true for both hardware and software development.

Consumers’ Concerns


1. Reduced Training Time and Cost

Training time can be significant for new employees, especially in an industry with high turnover.

The user-centered design process focuses not only on usability, but also on learnability of the system.

When an existing system is replaced with a new model, employees will likely need training. In a production environment or healthcare setting, there is no opportunity for down time while the staff gets up to speed. The user-centered design process can help reduce training time and associated costs.

2. Reduced Error Rates

Human factors engineering has focused on reducing error and increasing productivity since the field was born. With roots in both industrial engineering and psychology, the field grew with a focus on designing for the physical, perceptual, and cognitive limitations of human operators.

The costs associated with human error vary considerably. It is one thing to tap a wrong button on a keypad when entering an address into your car’s GPS, but another level of criticality altogether when setting a dose on an infusion pump or programming an airliner’s autopilot system. Some products clearly have significant personal, social, and financial consequences associated with use errors.

3. Increased Productivity

Productivity improvements can take various forms, including increasing speed and efficiency, reducing waste, decreasing the quantity of raw materials used, and reducing the physical strain on the operator to decrease injuries and absenteeism — to name a few. One of the most common things we do to help our clients is to eliminate unnecessary steps in workflows.

On one recent project we were able to reduce the time it takes an operator to perform a procedure by just a few minutes, allowing the end user to increase productivity dramatically over the course of a day.

As an added benefit, when operators feel more productive, their job satisfaction increases and so does employee retention.

Dollars and Sense

Clearly usability has big payoffs for both the manufacturer and the end users. Looking back on my career, thus far, I realize I’ve been fortunate to work in industries where there is generally a high level of usability maturity — where usability is king, or at least a product differentiator. From now on, when I encounter clients who are still learning about the return on investment of good UI design, I’ll leave the explaining to this post so we can move on more quickly to the valuable work of of user-centered design — either that, or send them to dinner with Cosmo.


Bias, R. and Mayhew, D. (Eds.), (2005) Cost-Justifying Usability: An Update for the Internet Age. San Francisco: Morgan Kaufmann.
Design Council (2004). The Impact of Design on Stock Market Performance: An Analysis of UK Quoted Companies 1994-2003. Retrieved from
Rae, J. (2013). What Is the Real Value of Design?. Design Management Review, 24, 30-37.
Smith, P. & Reinertsen, D. (1995). Developing products in half the time. New York: Van Nostrand Reinhold.