Validation of a home safety questionnaire used in a randomised controlled trial

The objective of this study was to measure the validity of self reported safety practices from a questionnaire, completed by families participating in a home safety randomised controlled trial. The postal questionnaire was used to measure secondary outcomes in a randomised controlled trial. The answers to 26 questions that could be assessed by observation were checked by a home visit. Families were invited to take part in a “home safety check”; they were not told that the visit was part of a validation study. At the time of the visit the researcher was blind to the self reports in the questionnaires. Results showed that sixty four questionnaires were validated by visits to 64 households. Percentage agreement ranged from 58% to 100%. Sensitivity was high (68% or above) for most safety practices. The positive predictive value was also high for most safety practices (78% or above for 15 of the 16 practices). In conclusion, this study found a fairly high degree of consistency between self reported data and actual observations. The findings from this relatively small study need confirmation from larger studies.