Superficially, it seems preferable to use objective performance data (such as productivity figures) when available, rather than subjective supervisory ratings to assess employees.
When might objective data be less effective as performance measures than are subjective ratings?
It is nice to use objective data to measure statistics such as sales made, productivity, number of phone calls. These are all quantifiable measures. However, not everything in a work description is in fact quantitative in nature. There is also a ...
The solution discusses when objective data might be less effective as performance measures than are subjective ratings.