title: [The effect of response behaviour on veterinary epidemiological studies--an analysis based on a cross-sectional study of livestock management of cattle farms in Lower Saxony].
abstract: Cross-sectional studies are used as an epidemiological instrument in several veterinary investigations. A common means of collecting information is the questionnaire, which is send to diagnostic units like farmers. A common fact is, that not all designated individuals take part. So it is to be clarified, if and in which concern this fact influences the results of an epidemiological study. Considering the example of a cross-sectional study in cattle farms this paper shows, that consistency of Responders and Non-Responders differs significantly. Technical measures to estimate this effect and consequences for the results are shown. Small and medium farms showed a different response rate than big farms before as well as after a mailed reminding letter. Considering the complete return period there was no significantly different response rate between farms of different sizes. Furthermore there are noticeable differences between Responders and Non-Responders concerning parameters like housing or use of commercial feedstuff. Therefore it is implicitly required to send a reminding letter and pursue Non-Responders in researches. Otherwise a biased sample collective is generated.
authors.affiliation: Institut für Biometrie, Epidemiologie und Informationsverarbeitung, Stiftung Tierärztliche Hochschule Hannover.
authors.forename: Amely
authors.initials: A
authors.lastname: Ovelhey
authors.forename: Martin
authors.initials: M
authors.lastname: Beyerbach
authors.forename: Lothar
authors.initials: L
authors.lastname: Kreienbrock
mesh_terms: D000383:Agriculture; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005858:Germany