The 16 UX Factors In The Point Of Sale System · POS Design Guide Part 1

The design of ePOS software is faced with a set of challenges that arise out of the unique context the software is being used in. As a UX design agency we have conducted numerous user research activities for our clients to understand how cashiers use ePOS software systems and how the user experience affects their job. Also, we have reviewed dozens of ePOS systems and are still fascinated how few of them have a user experience that enables cashiers to be proficient.

Regardless of whether the ePOS software solution is iOS, Android or web-based, the standard UX design patterns cannot be applied readily to ePOS software apps, because the context is different in many ways:

Context issues

The setting and the way in which cashiers use the ePOS system connected to the cash register is completely different from how someone might use any other tablet application. Here’s how:

Distance to screen

Tablets, phones and laptops can be moved and time people hold them at a comfortable distance of about 40 cm. Standard apps usability guides for sizes of fonts and buttons are based on this, but the same doesn’t apply to a POS software.

We have performed on-site research with cashiers in their real setting several times and the results show that the distance to the screen is usually least double that, even when the position of the ePOS on the counter can be controlled. But most cashiers cannot control the position of the ePOS display because they don’t have enough space on the counter.

Time pressure

While most apps pride themselves with how easy it is to do something and often times this is translated to marketing slogans that advertise speed, the fact is that consumers go through user flows at their own pace with hardly any time pressure.

Cashiers do not have this luxury: they have to engage with the ePOS interface as quickly as possible to prevent queues from forming. Countless user interviews and hours of observation in our user research have shown that the tapping speed for cashiers is at least double that of normal users. The pressure from the customers is real. This means that intuitiveness, coherence and reliability of the ePOS user interface have to reach a whole new standard that cannot be compared to standard apps.

Physicality

The user experience of the POS is not purely digital. In fact it is part of a larger setting that is very physical: the space around the counter, the layout of the store, the shape and size of products, the scanner, the card reader, other third party devices are all part of the user experience. The POS interface is a node that connects all these elements, but designers have to understand the real-life context and account for it in the POS interface design. Further, designers should not underestimate the variety of configurations all these physical factors manifest in all the store locations where a POS application will be used.

User factors

Any design approach must be mindful about limitations of users. The variety of people who operate POS systems is significant so there is a lot to say, but here are a few factors:

Attention resources

Even though people are distracted and many people do a few things while they also engage with an app (especially on mobile), they have considerable control over their attention.

Cashiers have to be aware of the larger context of the store, but also they have to engage with the customer, both visually and verbally to make the experience feel pleasant and personal. Affording attention to the ePOS interface is expensive and staring at the screen for a few seconds to interpret the design is a problem. Attention switching is a type of executive function that is very taxing on cognitive abilities and thus very tiring.

Visual impairment

User experience designers know that about 5% of the general population have some form of mild visual impairment. Many stores have lighting issues, either too little or too much: sometimes, lights may shine directly onto the screen and produce glare.

While general users have some control over the situation they use an app and they can mitigate these factors, cashiers have very little control and the software interface must be more accommodating of their needs.

And: cashiers use the software in a professional setting for hours on end and they constantly have to refocus on objects that are a varying distances. This situation is tiring for the eyes.


Read the Design Guide Part 2: The Design Principles In The POS System.

Left/right handedness

Inevitably some cashiers are left-handed. The POS display and interface is sometimes placed on the left and sometimes on the right of the counter. The user interface should take into account how the content interacts with hand gestures and the positioning of the system.

Process constraints

It is not unusual for business goals to be different from user goals. However, in the case of the POS software interfaces, there are a few more challenges that designers have to take into account.

Misconduct

Cashiers operate with money and some are tempted to appropriate a few quid here and there. In our research for POS projects we have spoken to many retail owner, both small and large enterprises. For all of them misconduct is a big loss and they are limited in how they can control the problem. And it is not just the loss to the bottom line, cashier misconduct creates an accounting mess.

The design of the ePOS user experience and user interface must be mindful of factors that encourage or discourage misconduct. A thorough understanding of common theft methods is important. In our research so far we have documented more than 15 ways in which employees steel money out of the cash register and some of these can be reduced by integrating smart design solutions into the ePOS software system. However, the benchmarking research we performed has shown that many interface in POS systems on the market are lacking effective ways to prevent fraud.

Errors affect speed

Most fraud methods involve simulating an erroneous transaction, thus the common user design principle of permitting errors cannot be applied out of the box. It has to be integrated in a thoughtful way. Either way errors will be taxing to the time spent per customer.

An error, and with hundreds of transactions per day errors are bound to happen, can easily increase the time spent per customer by a factor of 10. This is challenging for cashiers because they are in a situation where they have to be fast, but also not commit any errors in handling products in the ePOS. When an error occurs, the catch-22 is amplified a few times over and stress increases.

Accounting process

Using the cash register is essentially a book keeping process, thus the user experience designer must reconcile user needs with accounting procedures. Of course, accounting procedures are not designed to make the cashiers life easy, so the challenge for the design is to bridge the gap between the human being who is a cashier and the inhuman process of accounting. This is different from designing standard mobile apps, where designers can implement almost any solution that delivers the easiest way for users to achieve their goals.

Proficiency

Through the direct observation of how cashiers use POS interfaces in a real-life settings, we have been able to observe the differences between proficient users and less efficient users.

Proficient users

Users who are much faster than others differ in how they approach the use of the software, even when they have the same amount of experience as average users. Firstly, they put authentic effort into developing the dexterity to scan products with one hand while they use the other one to operate the cash register interface. Secondly, they experiment different methods to perform tasks and stick with the one that works best.

Average users are serene about doing things at an average page with average results, even when is a little effort could increase their efficiency. They do not like to experiment and to find hacks and they become stressed when they are uncertain about what to do.

The interface design must take into account the subtleties of both ways of using the ePOS software interface and to support both types of users in doing the best job they can.

Training

All cashiers receive a basic amount of training and most of them spend one or more days under direct supervision. This is not just a matter of learning to use the ePOS system, but also of learning all the other processes and behaviours that come with the job. It is difficult for cashiers to learn as they learn under extreme stress: both the customers and their supervisor are present while they have to perform new and complex tasks. Stress decreases people’s ability to learn.

Standard and non standard behaviour

While in principle using an ePOS software system is simple, the reality of the job is much more complex. User experience designers who approach the design challenge in an abstract way will have a difficult time creating a user interface that really works in practice.

In the dozens of hours of observation we have performed and during participative sessions where our designers have acted as cashiers, we have been able to observe a lot of exceptions to what IT managers expect to happen in reality. These are unusual situations that should not occur according to the rulebook, but they are very present in the actual day-to-day life of a cashier operating an ePOS system. The POS software design must be aware of these situations.

Take away

The design of ePOS systems must take into account how different this type of application is from anything else that UX designers typically do. The ePOS system is being used in an unusual setting, by people who are tired and who have to deal with other people. The ePOS is an essential tool that bridges the gap between what happens in the store and the accounting process — this adds a new layer of complexity. Each transaction is high stakes because it involves customer happiness and money — low error rates are important because they sometimes blend into fraud.

Thorough user research and a nuanced understanding of day-to-day reality are essential success factors for POS design projects.

If you are interested in more UX case studies, check out The Border Force Goes Digital on our website, https://www.interface-design.co.uk/.

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