I have two different tests that measure the skill of participants in two different fields, leading to two different test scores for each participant. I want to combine both test scores to get an overall test score for each participant.
I have a guide that suggests to do the following:
- Step 1: Compute the skill percentile compared to other participants for each participant separately for each of the two tests.
- Step 2: Take the average of both test percentiles for each participant.
For instance, person X has a test score percentile of 70 in test A and a percentile of 60 in test B, leading to a final test score of 65.
I'm wondering if this approach is leading to any bias, since I was assuming that you shouldn't just take the average of percentiles. Is it valid to take the average of two percentiles as described above?