Mobile Phone Usability

Given that usability makes a difference which may affect mobile handset purchasing choices, how should manufacturers ensure that their phones are easy to use and easy to learn? The golden rule, as Nokia know, is to involve users in design.

Mobile Phone Usability

Nokia are the world's leading maker of mobile phones. Their user-centred approach to developing products has been identified as one crucial factor behind this success. "Nokia starts its planning from what the consumer actually wants while Ericsson and Motorola tend to be more engineering driven" commented Mark Davies Jones of Schroder Solomon Smith Barney (Business Plus Online www.bizplus.ie, November 2000).

Anecdotal evidence and our own previous observations suggest that consumers find Nokia's mobile phones easier to use than many of their competitors and often take this into account - either consciously or sub-consciously - when making their purchasing decision. Frontend decided to evaluate the usability of a Nokia phone, the popular 3210, against a competitor, the older Siemens C25. We found that the Nokia is significantly easier to use in a number of areas.

Usability Evaluation Rates Nokia 3210 Above Siemens C25

We evaluated both phones to see how they conformed to usability principles. Here are some of our findings.

Complexity

The Nokia uses only three buttons for what the Siemens requires five buttons.

Consistency

The same buttons on the Siemens can serve different functions at different times (e.g. scrolling and selecting). This can be confusing for users. Button functions on the Nokia are consistent, with dedicated buttons for selecting, scrolling and cancelling.

Function/control mapping

Associating functions to controls is easier on the Nokia because the relevant text appears directly over the action button. This is not always the case with the Siemens.

Clutter

The Siemens phone makes heavy use of icons. However, these are not readily interpretable or noticeable because of their small size and varying locations on the display area. The overall effect is of a cluttered display that is potentially confusing and ultimately harder to use, despite giving more "information".

Accessibility

Users with deuteranopia colour blindness (who see reds and greens are seen as a similar, brownish colour) may find it difficult to distinguish between the functions portrayed by the Green (call) and Red (end call) icons on the Siemens phone.

Overall, the Siemens phone makes more options visible at any one time, but at considerable cost in complexity, consistency and clarity. This complexity makes the Siemens functions significantly more difficult to learn. Most mobile phone users do not read the manual in any detail, if at all. Instead, they discover features of the phone through a process of trial-and-error. If these features are difficult to learn or use, they may not be used at all, no matter how useful they are. Even worse, the anecdotal evidence that some consumers choose Nokia because they are easy to use suggests that poor "learnability" may well affect future sales.

How to Ensure Usability

So, given that usability makes a difference which may affect purchasing choices, how should manufacturers ensure that their phones are easy to use and easy to learn? The golden rule, as Nokia know, is to Involve Users in Design.

This means gathering detailed knowledge of users' requirements. For example, what tasks do they want to perform with their phone, in what circumstances and how frequently?

Once you have an initial design, you should thoroughly analyse its usability by carrying out user tests. The findings we have reported above are not from formal user tests but from our own informal observations and expert analysis. Although they point to some major usability differences, they are no substitute for formal user tests. A formal test involves you observing representative users carrying out representative tasks using the phone. This does not mean focus groups. Focus groups, though used extensively in product evaluation, do not produce useful insights into usability. What users say is not the same thing as what users do. The same goes for market research questionnaires. We sent a questionnaire to 30 people who use either a Nokia 3210 or a Siemens C25. We asked them how they rated the usability of their phone and found no significant difference in reported usability. Our observations contradict this.

User tests should be carefully designed to reflect real use and stages of use. You should take into account learnability as well as long term use. Because a mobile phone is a lifestyle device, you should test its use in a lifestyle setting with all the usual environmental constraints - on the train, in the car, in the pub, for fun and for business. Real situations of use are very difficult to simulate in a laboratory and make a big difference to users' experiences. A careful choice of different research methods may be needed in order to yield an accurate picture of user behaviour.