Case Study: Choosing an Exercise Mode in a Heart Rate Monitor Adapt Or Not To Adapt Case Study: Choosing an Exercise Mode in a Heart Rate Monitor Lauri Sumari 2002

A Definition Adaptive systems are systems which can alter aspects of their structure, functionality or interface in order to accommodate the differing needs of individuals or groups of users and the changing needs of users over time – Benyon et al. (1987)

Case: Heart Rate Monitor UI tested in the usability lab a pro model many features comes with a PC utility challenging constraints small screen few buttons only one menu item visible at a time

The Problem the monitor has 10 different exercise modes a pro user uses many modes regularly many exercises each day the mode must be chosen each time tradeoff: detailed data / input effort how to select the default exercise mode?

Key Characteristics a menu with many items only one item can be shown at a time default item carries most weight measurable variables correlate with menu item usage correlation is user-specific correlation changes over time machine learning?

Attributes of a Solution menu order? fixed, configurable, sorted default item? item number 1 most recent item most frequent item (adaptivity?) most likely item based on context (adaptivity)

How to Make the Choice? is the problem "hard enough"? is the adaptive approach feasible? limited processing power limited memory capacity what is the most usable solution? missing heuristics / design patterns must analyze options for both approaches

A Conventional Solution menu order: fixed or configurable default item: most recently used predictable easy to implement

An Adaptive Solution menu order: fixed or configurable default item: most likely operational life cycle initial phase transitional phase mature phase (watch out for abrupt change!)

Building the Adaptivity context variables day of week, time of day idle time, recent choices current heart rate pre-training at the factory tradeoff: head-start / miss penalty

A Critical Look the adaptive approach currently overkill but look at the future of adaptivity more common? reusable frameworks for implementation? similar usability challenges likely small computing devices proliferate