Sociodemographic Differences in Respondent Preferences for Survey Formats: Sampling Bias and Potential Threats to External Validity.

Objective: To explore sampling bias as a result of survey format selection by examining associations between characteristics of people aging with long-term physical disability (PAwLTPD) and their preferences for phone or web-based survey format. Design: A cross-sectional study using a secondary data analysis approach. Setting: Data were from an ongoing longitudinal cohort study conducted in the community. Participants: Convenience sampling was used. PAwLTPD who participated in year 2 of the longitudinal cohort study were included. Inclusion criteria were age 45-65 years, English speaking, and self-reported onset of a physical disability at least 5 years prior to study recruitment. Two participants completed the survey using both phone and web formats and were thus excluded; 387 participants (N=387) were included in the analysis. Interventions: Not applicable. Main Outcome Measures: Choice of survey format and demographics (age, sex, race and ethnicity, marital status, living arrangement, socioeconomic status) were collected in addition to self-rated physical health. Results: Participants were on average 58.2±5.6 years old. A total of 33% were male, and 62% were White. Approximately 40% of participants completed phone surveys. The phone survey group was significantly older ( Conclusions: Sociodemographics are associated with survey format choice in PAwLTPD. Findings largely support the existing understanding of digital literacy but also provide insight into the potential occurrence of sampling bias when multiple survey format options are not offered. These findings have implications for investigators who aim to reach a more representative sample of people with disabilities.