I am currently working on my thesis and am working on conducting an user research about chatbot experience with real users. Currently, I will test three different chatbot prototypes to test:
(1) For each prototype, I will find around 5-7 users to test it
(2) To test each prototype, I will first interview them (to know their usage of chatbot, background, etc.), then usability testing (giving them tasks), and finally I wan to use some metrics to measure how good is the prototype.
(3) I wonder if anyone recommends any metrics for measuring the usability of a chatbot app? I currently planned to use the SUS questionnaire, which I found a few theses using it to evaluate chatbot, but I am not sure if it works with a small number of samples (5 users).
Does anyone recommend some different approaches?