Validation of a home safety questionnaire used in a series of case-control studies

OBJECTIVE To measure the validity of safety behaviours, safety equipment use and hazards reported on a questionnaire by parents/carers with children aged under 5 years participating in a series of home safety case-control studies. METHODS The questionnaire measured safety behaviours, safety equipment use and hazards being used as exposures in five case-control studies. Responses to questions were compared with observations made during a home visit. The researchers making observations were blind to questionnaire responses. RESULTS In total, 162 families participated in the study. Overall agreement between reported and observed values of the safety practices ranged from 48.5% to 97.3%. Only 3 safety practices (stair gate at the top of stairs, stair gate at the bottom of stairs, stairs are carpeted) had substantial agreement based on the κ statistic (k=0.65, 0.72, 0.74, respectively). Sensitivity was high (≥70%) for 19 of the 30 safety practices, and specificity was high (≥70%) for 20 of the 30 practices. Overall for 24 safety practices, a higher proportion of respondents over-reported than under-reported safe practice (negative predictive value>positive predictive value). For six safety practices, a higher proportion of respondents under-reported than over-reported safe practice (negative predictive value<positive predictive value). CONCLUSIONS This study found that the validity of self-reports varied with safety practice. Questions with a high specificity will be useful for practitioners for identifying households who may benefit from home safety interventions and will be useful for researchers as measures of exposures or outcomes.