Chapter 13:
Evaluation is about how well a projects requirements are met by the design.
The DECIDE framework is a proposed framework to structure planning for evaluation.
DECIDE framework checklist:
- Determine the goals
- What are the goals of the evaluation? Who wants it and why? Goals guide the evaluation by helping to determine the goals.
- Explore the questions
- Taking the goals of the evaluation in consideration, formulate related questions to explore a possible issue.
- Choose the evaluation method
- Depending on what suits the situation best, choose a method of evaluation. Triangulation through multiple methods is sometimes the best solution.
- Identify the practical issues
- Choose the participants appropriately
- Make sure the facilities and equipment used is suitable for the evaluation study
- Consider schedule and budget
- Make sure the evaluation team has the expertise necessary to complete a proper evaluation
- Decide how to deal with the ethical issues
- When dealing with people for an evaluation these following points help ensure it is done ethically:
- Tell people the goals of the study and what to expect if they agree to participate
- Be sure to clarify that anonymity is to be upheld.
- Give participants the liberty to stop the evaluation whenever
- Ask for permission in advance to quote participants.
- Evaluate, analyze, interpret, and present the data
- Ask yourself the following:
- Reliability: Will others using the same method get similar results?
- Validity: Is the method measuring what is intended?
- Ecological validity: Does the location change how the participants react and behave?
- Biases: Are the evaluators being as objective as possible?
- Scope: How much can the findings of the study be generalized?
This list is not meant necessarily be followed in the order presented, rather be iterated upon since decisions about some items might impact others.
Chapter 15
This chapter is about methods that are based on understanding users through knowledge codified in heuristics, remotely gathered data, or models that predict users’ performance.
Heuristic Evaluation is a usability inspection method for user-interface elements that was developed by Nielsen and his colleagues. They came up with a set of principles that should guide design projects in a usability perspective. These principles include: Visibility of system status, Match between system and the real world, User control and freedom, Consistency an Standards, Error prevention, Recognition rather than recall, Flexibility and efficiency of use, Aesthetic and minimalist design, Help users recognise, diagnose, and recover from errors, Help and documentation.
These principles are pretty self-explanatory and sometimes even intuitive yet crucial to ask yourself throughout the design process to catch potential flaws.
Alternative approach to heuristic evaluation is Walkthroughs.
Cognitive Walkthroughs - Involves simulating a user’s problem-solving process at each step in the human-computer dialog.
Pluralistic Walkthroughs - A sort of roleplay where evaluators take the role of a typical user.
The GOMS model (goals, operators, methods, selection rules) - An attempt to model the knowledge and cognitive processes involved when users interact with systems.
The Keystroke Level Model - Provides numerical predictions of user performance. A task can be compared in terms of the time it takes to perform them.
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