The Attainment Index in this example is the aggregation of Dan, Carol and Bill’s Perceptions of Anna’s work. Bill thought that Anna did very well, Carol though she did well, and Dan though that Anna could have improved a few things.
You may be wondering why you were ranked as a 1 out of X in the group, but your Attainment Index was not at a 5. Well, that is because, going back to the picture above. Perhaps Anna’s Attainment index was 4.11. This was still higher than anyone else in her group, but, because Dan’s perception was a little lower, she did not get the full Attainment of 5.