Worker agreement with aggregate, or "Wawa", is a common, simple metric used in jobs that do not employ test questions. It is also known as "inter-rater agreement" or "co-worker agreement." These all refer to the same thing. They are a measure, for each contributor, that indicates the average number of times their response agreed with the aggregate answer for each unit.
For example, if my responses to 6 units were: A, C, B, C, B, D
And the aggregated answers to those 6 were: A, C, B, B, D, D
My Wawa is 67%, because my responses agreed with the aggregated answers only 4 out of 6 times.