Evaluating your designs with people is one of the important step in design process. It answers the question how the interface design would actually works in the real user’s hand. It provides designer feedback to validate the direction they are aiming for. It also answers the question of how to measure success.
Usability Studies or usability testing – bringing people in to test your prototypes with a specific target audience. The good side of it is that it is easy to observe and ask questions. It is also know as the controlled experiment, where it can limit the real-world applicability.
Survey and Focus Groups – the fastest and easy to get the feedback of a mock-up or wire-frame. The down side is what people actually does is often different than they said. Yet, it is still a useful tool to get feedback, which is often better than none.
Feedback from experts (peer critique, dogfooding, heuristics evaluation) – peer critique can done in your organization like peer review on weekly project (classroom setting) or other designers in your organization. Dogfooding is to eat your dog food yourself, meaning that using the tool yourself. It is better to have a rubric for your evaluation. Heuristics evaluation is pioneer by Jakob Nielsen for the UI testing.
Comparative Experiments – to take one or more comparative ingredients to see the actual behavior, which can be done in many environments. For example, a comparison of the help search function from one product to another one. It gives you an idea the conceptual model behind the help search function.
Participant Observation – if realistic longitude is you are after, participant observation is the suitable one. The controlled environment provides a better opportunity to observe people, while they are using the product.
Simulation and Formal Models – can be used for high level of cognitive tasks like designing a shorthand keyboard and search result.
Things to consider – evaluation techniques provide an incredible insight for your design process, but not all the techniques above can be perfect. You might need to take into consideration of resources and time in picking the right technique to evaluate your design. It all comes down to one question.