1. A rating system for NGO's helps to screen the NGO's for various purposes. It gives them a quality rating & accreditation in the process. Internationa standards like ISO, etc. envisage such ratings internally and externally. Whereever such systems were adopted, those organizations perform better than others because a sense of committement, continual improvement, etc. are inculcated.

2. The rating shall be based on multiple criteria, which shall be decided by the authority. You will find a large variation even in trusts, charities, etc. An accreditation process helps standardizing the cirteria.

3. A third party like a Regulatory Authority (Telecom, Insurance, Stock Exchange, University etc. ) is desired. Many examples can be quoted.

4. Many NGO's are doing outstanding and pioneering work in their limited domains. They may be effective in a given location and they may not be effective in other locations. Most NGOs enjoy grassroots support in the localities.