Chapter 13, Evaluation Framework
To check that the development of a product is going in the right direction it needs to be evaluated. Evaluating a product is done by asking wide and narrow questions about how the user interact with a product, for example "Do they enjoy it?" or "Will they find this menu option?".
To normalize the evaluation process and make sure important details aren't missed there has been developed a framework called D.E.C.I.D.E.. This is what each letter stands for:
1. Determine the goals
Determine and decide the goals and scope of the evaluation.
2. Explore the questions
Make the questions that will lead to the goal of the evaluation clear.
3. Choose the evaluation methods
The method depends on the type of product or stage in development process. It can for example be a usability test in a laboratory or an In The Wild study.
4. Identify the practical issues
Issues can easily be identified by doing a pilot study before the real one. The issues can for example be how to get appropriate participants for a test, knowing how long the test will be and what the participants will do, if you try to create a natural setting how would the evaluator not affect the result of behavior, where will the study be held and what equipment is needed, what does the budget allow, what kind of evaluator expertise is needed and so on...
4. Decide how to deal with the ethical issues
There are rules about how participants and their privacy needs to be protected. Sometimes there needs to be a consent form for participants to sign. The participants must be fully in the know about what data will be used for and if it will be stored or not. Guidelines to protect online users are being developed (it takes time to make guidelines).
5. Evaluate, analyze, interpret and present the data
The evaluator needs to be clear about the studie's reliability, that the same method was used throughout, its validity, that the method measured the actual issues in question, its ecological validity, that the method was carried out in a laboratory and the results can be applied to the real world or not, biases that evaluators have making them focus on certain kinds of data and affect the result, and the studie's scope which is the extent to which the results can be generalized when all real life factors cannot be taken into account.
Chapter 15, Evaluation: Inspections, Analytics and Models
These methods of evaluation can be used without having any user participants in tests, which can save time and money.
Inspections: The Heuristic Evaluation method consists of heuristics developed to be generalized over many products. Each heuristic concerns one area of usability of the product. Experts are hired to go through all the heuristics and they manage to find most usability problems with a product. Another inspection method is the walkthrough, where experts create user scenarios and walk through the use of the product together acting as users. This gives very detailed answers about users thought process.
Analytics: Analytics can be used to evaluate how for example a website works by giving the evaluators data about where users click, how long time they spend on certain pages and so on. It's a very cheap method since the data is obtained without having to hire experts, you just use a program.
Predictive models: Without trying out the product, formulas can be used to estimate information about the product. The GOMS model is used to describe step by step every action and thought a user will go through when completing a task using the product. When these are out on a paper it is easier to developers to see where trouble might occur and change the design to make usability better. The Keystroke Level Method is even more specific, for every step taken when carrying out an action with a keyboard there is an estimated time that can be added together to see what the total time for a task for a user will be. The problem with these methods are their scopes, they don't take mistakes or a users obtrusive surroundings into account.
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