Validity

We assessed content, face and construct validity of the Persian version of the LSP-R questionnaire using qualitative and qualitative methods.

Content validity: Five experts including one linguists two medical educationists and two health professionals checked the questionnaire for possible syntactic errors, and proper allocation of items. As quantitative measures, content validity index (CVI) and content validity ratio (CVR) were then checked (9). CVI was calculated using a Likert-type ordinal scale (from 1=very relevant to 4=not relevant). Using experts’ opinions CVI was calculated as the proportion of items that received a rating of 3 or 4 (9). For calculating CVR each item was rated as essential, useful but not essential, or not essential (10). After performing validity tests, four items excluded from original version.

Face validity: Initially 10 students were asked to state if they feel any kind of ambiguity in responding the questionnaire. In case they had any difficulty, they were noted to refine the questionnaire. In the quantitative phase, the impact score (frequency × importance) was measured using the opinions of the recruited students. Impact score equal or greater than 1.5 was considered appropriate (11).

Construct validity: This was checked using expletory factor analysis (EFA) to determine the underlying constructs of the questionnaire.