Comparison of telephone and in-person interview modalities: duration, richness, and costs in the context of exploring determinants of equitable access to community health services in Meru, Kenya

Background: Our research team is conducting phenomenological interviews in Kenya with people who have not been able to access community eye health services, aiming to explore the barriers and ideas for potential service modifications. We conducted an embedded study that compared in-person and telephone interview modalities in terms of time requirements, costs, and data richness. Methods: A team of six interviewers conducted 31 in-person interviews and 31 telephone interviews using the same recruitment strategy, topic guide, and analytic matrix for each interview. We compared the mean duration; mean number of themes reported by each participant; total number of themes reported; interviewer rating of perceived richness; interviewer rating of perceived ease of building rapport; number of days taken by the team to complete all interviews; and all costs associated with conducting the interviews in each modality. Findings: In-person interviews were 44% more expensive and took 60% longer to complete than our telephone interviews (requiring 5 days and 3 days respectively). The average in-person interview lasted 110 seconds longer than the average telephone interview (p=0.05) and generated more words and themes. However, the full set of interviews from both approaches identified similar numbers of barriers (p=0.14) and the same number of solutions (p=0.03). Interviewers universally felt that the in-person approach was associated with better rapport and higher quality data (p=0.01). Triangulation of themes revealed good agreement, with 88% of all solutions occurring in both sets, and no areas of thematic dissonance. Discussion: The in-person approach required more time and financial resources, but generated more words and themes per person, and was perceived to afford richer data by interviewers. However, this additional richness did not translate into a greater number of themes that our team can act upon to improve services.