Comprehensive vs Thin Rating

What is the difference between a 'comprehensive' rating and a 'thin' rating?

There are broadly two different products that are likely to be available: a 'comprehensive' rating and a 'thin' rating. Both kinds of rating include meetings with program management and review of internal information to assess operational capacity to achieve social goals. The difference between the two rating approaches lies in the fact that the comprehensive rating includes client level information to assess outreach and quality services, and collects this information as part of the rating exercise if it is not available with the MFI, while the thin rating relies on available information which may consist of outputs (in terms of for example, number of products, average loan size.)

The current phase of piloting social ratings involves comparing the two approaches in terms of the value added by the comprehensive approach, at an additional cost compared to the thin rating. Two of the rating agencies - M-CRIL and Microfinanza Rating - are testing both approaches, and will be able to offer both a comprehensive and thin rating. Planet Rating and MicroRate currently plan to offer the thin rating product. Product decisions will depend on evidence that client level information may be essential to making a robust assessment of social performance in practice, and that this justifies the additional cost involved (for field level data collection).

The costs of social rating vary by rating agency. The prices can vary a lot depending on the dimension of the MFI, its geographical coverage (dispersion of clients); the quality of the information available at the institutional level and whether or not the social rating is done together with a credit rating which reduces the cost. Generally, a thin social rating (without field survey) may cost between 30% and 60% of a credit rating, while a comprehensive social rating (with survey) between 90% and 150% of a credit rating.