Different methodologies are used by different agencies. There are many equally credible service providers such as MoneyControl, CRISIL, Value Research and MorningStar - and then there is Scripbox which goes beyond just rating and actually picks a recommended portfolio.
The high rated funds from each rating provider may differ from each other and also from Scripbox based on multiple factors. For example we consider a 4 year track record whereas Moneycontrol/CRISIL appear to consider only 3 years.
At Scripbox we publish our track record transparently and we also do an annual review of our performance which is published on our blog. With no other service provider will you find a published track record of their past recommendations.
It is also our belief that fund recommendation is only one part of successful investing. We also enable a disciplined investment process which includes annual review of portfolio and tax-efficient re-balancing designed to automate best investment practices.