Think of credit rating as a simple grading system where the top students perform the best on tests (making money) and those at the bottom are the biggest risk for dropping out of school (defaulting).

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Another approach uses numeric or qualitative ratings, such as one through five, critical, important or unknown, or even a simple high, medium, and low rating.

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You can search the programs by rating, topic, or by a simple keyword search.

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But he says the scoring system across the NHS must be simple to help people compare different trusts - like the five-star rating on TripAdvisor or eBay.

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The app might have been simple but it proved hugely popular with more than 250, 000 downloads and a superb user rating of 4.2 out of five.

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The simple message from Moody's to Germany is that it won't retain its AAA rating if the eurozone continues on its course of muddling through each successive crisis.

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