The Specific target user group consisted of 10 users, all Ericsson employees, and belonging to the consumer segment Techno-Pioneers. Seven of them were men and three women (mean age 32 years). All of them were familiar with computers. Average use amounted to > 10 hours/week.
The Particular environment was the following: The novice user was given 10 minutes to familiarise her/himself with the Smart Phone prototype. A manual was available during this time only.
The Specified goals consisted of 6 typical tasks that were presented in "logical" order: Insert charger, a warm-up task (Task 0). Enter two visit cards in the Address book (Task 1, 243 characters). Call a previously entered visit card name (Task 2). Create an e-mail (Task 3, 36 words, 177 characters). Send the e- mail (Task 4), Answer call when in organiser (Task 5) and Make an appointment in the Calendar (Task 6). Task 1, Task 3 and Task 6 were classified as major tasks. Six of the users received the tasks in ascending order (Task 0-6) whereas 4 users received the major Task 6 before the other two major tasks (Task 1 and 3).
The Effectiveness criterion was set according to ETSI's suggestions ( 1995) stating that "75% of a target user group should be able to accomplish a task in a service (in a system) on their first attempt." (Effectiveness Pass ≥ 75%). If the user asked for help or did not succeed in accomplishing the task correctly this was classified as Fail.
Task navigation depth for tasks performed using the organiser side was computed as task item depth + number of new windows/dialog boxes the Optimum path user ( Mohageg 1992) would have to navigate through (tap on) in order to complete a task correctly. Thus, taps necessary to move within the same window were not counted whereas taps necessary to navigate between different windows/dialog boxes were counted. Optimum path is defined as the shortest (navigation) route through a network of nodes to successfully solve a task. The procedure could be regarded as a simplified form of a GOMS (Goals, Operators, Methods and Selection rules) analysis ( Card, Moran and Newell 1983) where interaction is divided up into perceptual, motor and cognitive units. The prime focus of study was the cognitive overhead associated with navigation between windows/dialog boxes.
Task item depth + number of new windows/dialog boxes that the user had to navigate through (tap on, using the stylus) using Optimum navigation path in order to accomplish Task 1 correctly (for entering the 1st visit card only)