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Lessons Learned from Two Cohorts of Personal Informatics Self-Experiments

Self-experiments allow people to investigate their own individual outcomes from behavior change, often with the aid of personal tracking devices. The challenge is to design scientifically valid self-experiments that can reach conclusive results. In this paper, we aim to understand how novices run self-experiments when they are provided with a structured lesson in experimental design. We conducted a study on self-experimentation with two cohorts of students, where a total of 34 students performed a self-experiment of their choice. In the first cohort, students were given only two restrictions: a specific number of variables to track and a set duration for the study. The findings from this cohort helped us generate concrete guidelines for running a self-experiment, and use them as the format for the next cohort. A second cohort of students used these guidelines to conduct their own self-experiments in a more structured manner. Based on the findings from both cohorts, we propose a set of guidelines for running successful self-experiments that address the pitfalls encountered by students in the study, such as inadequate study design and analysis methods. We also discuss broader implications for future self-experimenters and designers of tools for self-experimentation.