CONDUCTING A TEST #9

Deciding on a test technique

The various observational techniqes are:

Think Aloud- Many published usability specialists believe that the think aloud method, "may be the most valuable usability method" (Neilsen, 1993). This method is based on having the participant talk as he/she works through the different tasks. The benefit of this technique is that more information on what the participant's thought processes are, why he/she does particular actions, and what his/her conceptual model, can be collected. This process of thinking out loud is an unnatural practice which means the participant will often need reminding throughout the tasks. To ensure the participants is comfortable with thinking out loud and understand what the testers are expecting it helps to demonstrate thinking out loud to the participant." ( Neilsen, 1993; Dumas and Redish, 1993; Rubin, 1994)

Co-discovery/collaberative/constructive approach- In this situation there are two participants work together to perform the tasks (Kennedy, 1989, In what). Participants are encouraged to talk to each other as they work through the tasks. This technique is easier for participants to do since it involves talking to another person, which is more natural than thinking out loud alone. This usually yield more info about what the users are thinking and what strategies they are using to solve their problems. Hackman and Biers (1992, in Neilsen) found that having two people work together does not distort other results (performance or preference), think aloud, active intervention, pure observation. Co-discovery is more expensive (two people per session) and is more difficult to watch two people working with each other and the product than just one (Neilsen, 1993)

Active intervention- when a member of the test team sits in the room with the participant and actively probes the participant's understanding of whatever is being tested. By asking probing questions throughout the test, rather than in one interview at the end, the tester can get some insight into participants' evolving mental model. This technique is particularly useful early in design (prototypes, design concepts), because it provides a wealth of diagnostic information. When preparing to use this technique in a test the goals, team concerns, and questions should be planned in advance. Special care should be used when designing questions so that they do not bias participants by being leading questions (Neilsen, 1993).