Screening optometric patients by questionnaire: methods of improving response

Mailed questionnaires are a quick and cheap means of obtaining data, but they have two disadvantages. They often produce low response rates irrespective of the nature of the group sampled, and they may seem inappropriate for clinical samples with visual problems. High response rates are needed for reliable results and valid conclusions. This paper presents a set of techniques enabling high response rates to be obtained. It also reports research showing that such techniques are appropriate even for the partially sighted.