Validity and measurement invariance across sex, age, and education level of the French short versions of the European Health Literacy Survey Questionnaire.

The French version of the HLS-EU-Q16 has acceptable psychometric properties, despite meaningful DIF for age, sex and education level and a poor discriminative power among subjects with average to high HL level. We recommend its use to measure HL in populations with sufficient reading skills to discriminate between subjects with low to average HL. Also, sensitivity analyses should be performed to evaluate the potential measurement bias due to DIF. Our results did not demonstrate the validity of the HLS-EU-Q6.