A validation study of the spoken knowledge in low literacy in diabetes scale (SKILLD)

In 2005 the Spoken Knowledge in Low Literacy in Diabetes scale (SKILLD) was introduced as a diabetes knowledge test. The SKILLD has not been validated since its introduction.

To perform a validation analysis on the SKILLD.

Cross-sectional observational study of 240 patients with diabetes at an academic family practice center.

SKILLD's correlation with an oral form of the Diabetes Knowledge Test (DKT) was used to assess criterion validity. A regression model tested construct validity, hypothesizing that SKILLD score was independently related to health literacy and education level. Content validity was tested using Cronbach's Alpha for inter-item relatedness and by comparing SKILLD items with the content of a National Institutes of Health (NIH) diabetes education website. We assessed inter-rater reliability and bias using Spearman correlation coefficients and sign-rank tests between interviewers scoring the same interview.

The SKILLD demonstrated fair correlation with the DKT (Pearson's coefficient 0.54, 95% CI=0.49 to 0.66, p<0.001). Health literacy, education level, male gender, household income, and years with diabetes were independent predictors of SKILLD score in the regression model. Cronbach's Alpha for inter-item relatedness was 0.54. There were some topics on the NIH website not addressed by the SKILLD. The inter-rater correlation coefficient was 0.79 (95% CI 0.56 to 0.91, p<0.001).

The SKILLD is an adequate diabetes knowledge test and is appropriate for people of all literacy levels. However, it should be expanded to more completely evaluate diabetes knowledge.