Testing interventions to improve response to a National Health Service Staff Survey.

The National Health Service Staff Survey is an annual, England-wide survey of staff employed by National Health Service organisations. It is administered using online and paper questionnaires. Response rates have fallen over time, while the proportion of staff receiving the online version - which historically has a lower response rate - has increased. Three interventions to increase online response were tested using an experimental design: more reminders; change of signatory to the invitation to participate and concise messaging in the invitation. Thirteen thousand staff members in five National Health Service trusts received the online survey. Results were analysed using contingency tables and logistic regression to determine the effect of interventions independently and in combination. More reminders improved response by six percentage points (odds ratio 1.33, 95% CI 1.23-1.43) and concise messaging by two percentage points (odds ratio 1.08, 95% CI 1.00-1.17). Change of signatory had no statistically significant effect and neither did any combination of the interventions. Given that costs for the successful interventions were minimal, more reminders in combination with concise messaging are recommended as a strategy to improve online response to the survey.