Are ratings becoming too lenient?

Very few firms give their top-most* ratings to more than a quarter of their workworce, but many are generous about giving 'second-highest' ratings

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* A 'top rating' implies a score of 5 on a 5-point scale (or a 6 on 6) score whereas a 'top 2 rating' would imply a score of 4/5 on 5 (or 5/6 on 6)