Temporal considerations for self-report research using short message service

When using Short Message Service (SMS) as a tool for data collection in psychological research, participants can be contacted at any time. This study examined how sampling frequency and time of day of contact impacted on response rates, response completeness, and response delay in repeated measures data collected via SMS. Eighty-five undergraduate students completed a six-item self-report questionnaire via SMS, in response to 20 SMS prompts sent on a random schedule. One group responded across 2 days, the other on a compressed schedule of 1 day. Overall, there was a high response rate. There was no significant difference in response rate, completeness, and delay of those responding across 1 or 2 days. Timing between prompts did not impact on response behavior. Responses were more likely to be complete if prompts were sent during the working day. The shortest time between prompts was 15 min, however, and use of an undergraduate sample limits generalizability. When conducting repeated measures sampling using SMS, researchers should be aware that more frequent sampling can be associated with poorer data quality, and should aim to collect data during the working day rather than mornings or evenings.