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4. Evaluation Methods

Version 6.1 by Mohamed Elsayed on 2023/04/11 14:11

There are several frameworks available for evaluating a prototype, one of which is DECIDE (Kurniawan, 2004), which stands for:

  • Determine the goals
  • Explore the questions
  • Choose evaluation approach and methods
  • Identify practical issues
  • Decide about ethical issues
  • Evaluate, analyze, interpret, and present data

To begin, the high-level goals of the study and the underlying motivation behind them are determined, as these factors can influence the approach taken. Next, the evaluation approach and methods should be selected, taking into account whether they will be based on quantitative or qualitative data, and how the data will be collected, analyzed, and presented. Any practical issues, such as participant recruitment, budget, or scheduling, are identified, and a pilot study is conducted. It is crucial to follow ethical procedures to ensure that participants are aware of their rights and are protected. Finally, the data should be evaluated to determine its reliability, validity, potential biases, environmental influences, and generalizability.

There are two types of evaluation methods: formative and summative evaluation. Formative evaluation is based on open-ended questions that focus on specific interaction processes, while summative evaluation looks at the overall effect and determines whether the objective has been achieved. Both qualitative and quantitative data can be used to measure these evaluations. Qualitative data is used to explore and identify patterns and themes, while quantitative data is used to describe, explain, and predict outcomes. Combining both types of data is often the best approach to evaluation.

What to measure to assess effects?

  • Objective measurements
    • Efficiency: time
    • Effectiveness: performance outcomes (errors, restarts, ...)
  • Subjective measurements
    • Satisfaction, pleasure/well-being, mood, excitement, likability
  • Validated questionnaires
    • System Usability Scale (SUS)
    • Affect Button 
    • Godspeed questionnaire 

1. Kurniawan, S. (2004). Interaction design: Beyond human-computer interaction by Preece, Sharp, and Rogers (2001), ISBN 0471492787.