Modification and validation of the Revised Diabetes Knowledge Scale

Objectives: To develop a simplified true/false response format of the Revised Diabetes Knowledge Scale and assess scaling assumptions, reliability and validity of the binary response format (the Simplified Diabetes Knowledge Scale) and compare with a multiple-choice version.

Methods: Ninety-nine respondents attending an outpatient clinic completed the multiple-choice version of the Revised Diabetes Knowledge Scale and the simplified version of the Revised Diabetes Knowledge Scale. The response patterns and psychometric properties of both questionnaires were assessed in order to test the construct validity of the simplified version.

Results: The mean age of the respondents was 57 years (range 21-83 years) and 64% were men. Respondents attained an average score of 65% on the Simplified Diabetes Knowledge Scale, compared with 62% on the Revised Diabetes Knowledge Scale. Overall, the Simplified Diabetes Knowledge Scale appeared to be somewhat easier to complete compared with the Revised Diabetes Knowledge Scale, as indicated by the number of missing responses.

Conclusions: The Simplified Diabetes Knowledge Scale provides researchers with a brief and simple diabetes knowledge questionnaire with favourable psychometric properties. The scale may require further updating to include other items relevant to diabetes education. This simplified version will now undergo translation and validation for use among minority ethnic groups resident in the UK.