A methodological review of solicited diaries as a qualitative tool in health research in low- and middle-income countries

Diaries have served as a vehicle to document personal narratives and as a research tool. However, diaries remain relatively underutilized in most research disciplines, particularly in the field of global health. This review aimed to explore the application, utility, and methodological potential of diaries as a qualitative data collection tool in the health sector within low- and middle-income countries. We applied a search string across several databases, which yielded 1796 articles that were screened for eligibility. Eleven articles, covering topics including menstrual health, HIV, and mental illness, met our criteria and were included in this review. Across studies, authors highlighted a need to provide instructions in a diary's early pages and make diaries appealing to the participants by incorporating color. Researchers and participants described diaries as an appropriate tool for conducting research especially among vulnerable populations (e.g. children) or on sensitive or stigmatized topics (e.g. HIV and menstrual health). Some participants said that diary entry clashed with existing obligations, leading to time conflicts and increased workload. Challenges related to diary comprehension suggests a need for researchers to engage more pointedly with participants to co-design diaries in a manner that facilitates understandability (e.g. language, use of audio/video recording among low literacy population) and age-appropriateness. An undercurrent across studies entailed a tension between what researchers desire from diaries (insights regarding a phenomenon of interest captured in a relatively timely manner) versus the original purpose of diaries (a space for individuals to note a variety of topics at a self-appointed pace). Studies generally under-report process insights from participants. Most studies stem from 2020 onward suggesting that this qualitative approach may continue to expand in the future. Our review organizes pertinent diary characteristics into a framework that may facilitate reporting of diary usage in global health research.