For a given comment , and subset (group) in the conversation , the Representativeness of that comment for group (denoted ), is a measure of how much more likely participants in group are to place vote on said comment than those outside group .
Here's how we compute Representativeness :
We first estimate the probably that a person in a group votes on comment as follows: . Here:
- is the number of people in group who vote (gree or isagree or ass) on comment
- is the number of people in group who vote at all on comment .
- The values of 1 & 2 added to the numerator and denominator of the above fraction are psuedocounts, and are used as a semi-naive prior in frequentist statistics.
We then compute
- Here is the complement of , that is, all the participants in the conversation who are not members of group .
Selection criteria are a bit more challenging to describe, but this involves looking at the two-property test (basically the fisher test) and multiplying this by the Representativeness to obtain a mashup number reflecting both estimated effect size and confidence.