Introduction: Pain diaries are important tools for clinical trials and optimal assay sensitivity of outcomes derived from these diaries is a worthwhile goal. Jensen and colleagues recently reported results suggesting that single-day diary-based outcomes could possibly be as psychometrically sound as outcomes based on taking the average of many diaries.
Materials and Methods: In this paper, we attempted to replicate those results with several diary data sets.
Results and Discussion: We come to a different conclusion than that advanced by Jensen and colleagues and conclude that their results were unusual in that very high test-retest reliability among days was found. With our 4 diary data sets we find that aggregating multiple diaries yields more reliable outcomes and improved sensitivity. We suggest that using single-day diaries will often lead to underpowered studies and that pretesting is advised before adopting single-day diaries. We also suggest that other researchers replicate these findings within their diary-based clinical trials.