Chapter 21 Deciding on what you need to evaluate: the strategy

Creating an Evaluation Strategy What Is the Purpose of This Evaluation? Does system meet usability requirements/concerns Qualitative Usability Requirements Desired features “The users on an e-shopping site should be able to order an item easily and without assistance.” “Railway clerks work in extremely noisy environments, so any warning messages to them should be visually distinct and highlighted on the screens.” UIDE Chapter 21

Creating an Evaluation Strategy Quantitative Usability Requirements/Usability Metrics Explicit measures used: percentages, timings, or numbers are used. “It should be possible for the users to load any page of a web site in 10 seconds using a 56K modem.” “It should take no more than two minutes for an experienced user (one who has domain knowledge and has undergone the prescribed level of training when the new system is introduced) to enter a customer’s details in the hotel’s database” UIDE Chapter 21

Creating an Evaluation Strategy Prioritizing Usability Requirements and Concerns The usability requirements most important to the success of the system are given priority. Assign values to the five dimensions of usability, the Five Es. UIDE Chapter 21

UIDE Chapter 21

Online Museum Exhibition UIDE Chapter 21

General Museum Site UIDE Chapter 21

Creating an Evaluation Strategy What Type of Data Do I Want to Collect? Quantitative data Numeric content Qualitative data Non-numeric content UIDE Chapter 21

What Constraints Do I Have? What Am I Evaluating? What Constraints Do I Have? Money Timescales Availability of usability equipment Availability of participants and the costs of recruiting them Availability of evaluators Documenting the Evaluation Strategy UIDE Chapter 21

UIDE Chapter 21

The Global Warming UI: The Evaluation Strategy Deciding What to Test Do You Have to Work within Any Constraints? Writing Up Your Evaluation Strategy for the Global Warming Evaluation UIDE Chapter 21