Purpose: Stigma negatively affects the quality of life of leprosy-affected people. Instruments are needed to assess levels of stigma and to monitor and evaluate stigma reduction interventions. We conducted a validation study of such instruments in Tamil Nadu and West Bengal, India.
Methods: Four instruments were tested in a 'Community Based Rehabilitation' (CBR) setting, the Participation Scale, Internalised Scale of Mental Illness (ISMI) adapted for leprosy-affected persons, Explanatory Model Interview Catalogue (EMIC) for leprosy-affected and non-affected persons and the General Self-Efficacy (GSE) Scale. We evaluated the following components of validity, construct validity, internal consistency, test-retest reproducibility and reliability to distinguish between groups. Construct validity was tested by correlating instrument scores and by triangulating quantitative and qualitative findings. Reliability was evaluated by comparing levels of stigma among people affected by leprosy and community controls, and among affected people living in CBR project areas and those in non-CBR areas.
Results: For the Participation, ISMI and EMIC scores significant differences were observed between those affected by leprosy and those not affected (p = 0.0001), and between affected persons in the CBR and Control group (p < 0.05). The internal consistency of the instruments measured with Cronbach's α ranged from 0.83 to 0.96 and was very good for all instruments. Test-retest reproducibility coefficients were 0.80 for the Participation score, 0.70 for the EMIC score, 0.62 for the ISMI score and 0.50 for the GSE score.
Conclusion: The construct validity of all instruments was confirmed. The Participation and EMIC Scales met all validity criteria, but test-retest reproducibility of the ISMI and GSE Scales needs further evaluation with a shorter test-retest interval and longer training and additional adaptations for the latter.