Development and Validation of the Diabetes Mellitus Knowledge Scale: A Validity and Reliability Study

INTRODUCTION: Diabetes Mellitus (DM) is a common non-communicable disease globally. Since children spend a significant amount of time at school, collaboration with school staff is essential for managing both emergencies and long-term complications related to DM. Therefore, assessing the knowledge level of school staff about DM is of great importance. This study aimed to develop a Diabetes Mellitus Knowledge Scale (DM-KS) and to conduct its validity and reliability analysis among teachers.
METHODS: This methodological study was carried out with 379 teachers working under the Altındağ District National Education Directorate during the 2022–2023 academic year. The DM-KS consists of 23 items. Validity was assessed through content validity, item analysis, and exploratory factor analysis (EFA), supported by intergroup differentiation. Reliability was evaluated using Cronbach’s alpha coefficient. Statistical analyses included Mann-Whitney U and Kruskal-Wallis tests.
RESULTS: The DM-KS comprises two subscales: “DM General Information and Symptoms” (11 items) and “DM Treatment and Complication Management” (12 items). Item difficulty indices ranged between 0.37 and 0.84, and discrimination coefficients ranged between 0.40 and 0.91. According to EFA, four items were excluded due to overlapping factors, and the factor loadings of the remaining items ranged from 0.39 to 0.76. The explained variances of subscales 1 and 2 were 38.2% and 41.4%, respectively. Cronbach’s alpha values were 0.84-0.87. Participants who had received training scored significantly higher in both subscales.
DISCUSSION AND CONCLUSION: The DM-KS is a valid and reliable instrument and may be further refined in future studies involving different groups.

Keywords: Type 1 diabetes mellitus, diabetes knowledge, diabetes knowledge scale, school health, psychometrics, validity and reliability