VALIDATION OF A POULTRY BIOSECURITY SURVEY

A questionnaire for farm managers was designed, to obtain information regarding biosecurity on Ontario commercial broiler chicken and turkey operations, and then pre-tested. The questions that could be validate d were verifiable by seeing the facility, by using farm records or by interviewing technical personnel other than the survey respondent. The survey was validated using a convenience sample of 24 farms from two companies. For 15 questions with dichotomous responses, the sensitivit y ranged from 16.7 to 100%; the specificity ranged from 0 to 100%. For example, fences and gates seen during the farm visit were not accurat ely reported on the survey (poor sensitivity). Chance-corrected agreem ent was low (kappa < 0.4) for 34 questions, fair to good (0.4 < kappa < 0.8) for 25 questions, and excellent (kappa > 0.8) for seven questio ns. The percent agreement for questions where only one of the possible options was observed on validation ranged from 60.9 to 100%. Five que stions with continuous numeric variables were analysed. A difference w as observed (P < 0.1) between the survey and validation data for three questions regarding the number of birds, the bird sources and the dow ntime between flocks. In spite of pre-testing, the lack of clear wordi ng and the absence of definitions for technical terms appeared to redu ce validity. Response bias seems to be an issue with biosecurity surve ys. The value of validating questionnaires before their use in epidemi ologic research is confirmed. (C) 1997 Elsevier Science B.V.