FA Digest scoring
The scores are chiefly based on popularity.
The base score depends on the number of favorites and the number of days since upload. The more favorites, the higher the score; the more recent the submission, the fewer favorites needed to reach a certain score. (For example, it normally takes 33 favorites to get a score of 1, but a piece submitted a day ago needs only 13.) The minimum base score, for a piece with 0 favs, is -6; there is no upper limit, but higher scores are increasingly harder to attain.
The base score gets a modifier for the piece’s content rating; general-audience work gets +1, and adult work gets -1. This is intended to offset the relative popularity of these categories. ’Mature’ work does not get this modifier. (Adult and mature pieces used to be part of the digest, but they proved to be surprisingly unpopular, and so to save time are no longer added.)
The next modifier is my opinion of quality: acceptable pieces get +1, and those that for some reason or other are disliked get -1. A final score can thus be any number greater than or equal to -8.
In the older digests all pieces scoring 5 or higher were included in the digest; more recently the minimum has been raised to 7. ‘Honorable mention’ works may be included; these are things I think should be included even though they don’t meet the minimum inclusion score.