When I was reviewing "First Posts" just now, there were two posts to be reviewed. I clicked "No Action Needed" for the first one, then a review audit came up (which I passed). Other times, when I review about seven posts in a row, no review audits come up.
How does the website decide, "Ok, it looks like this user needs to be tested... is he / she paying attention?" Is it completely random, or is there actually an algorithm or something for audits?