So WTF is a “Shot Equivalent?”
Short answer: Shot equivalents take free throws into account. So for simple math, look at the box score. Take each FGA and FTA. Each FGA is 1 equivalent (because due) and every 2 FTA is 1 equivalent. So if a player has attempted 5 shots from the field, and 4 free throws, they have 7 “shot equivalents.” Essentially you are just mashing FGA and FTA into a single stat. Or in slightly more “advanced” terms, giving TS% while including the volume of shooting.
A shot equivalent is a way of measuring how many possessions a player took with a shot attempt. If you take a shot but are fouled (and miss, more on and-1s in a moment) that does not count as a field goal attempt, however when you go to the line and shoot 2 free throws, you are finishing the possession. So if you miss both free throws (this is prudent for Pistons fans with Andre Drummond around) it does not hurt your FG%, but it is just as bad as missing a single field goal. In the same vein, hitting both free throws is just as good as hitting a single 2 point shot. Of course this means that if you want to be exact you must keep track of “and-1s” because an “and-1” free throw would not actually add a possession. So if a guy took 2 free throws in a game but they were both “and-1s” then it actually should not count as an extra possession. But that is kind of hard to keep track of so it is much easier to just count 2 free throws as 1 equivalent, and if there is an odd number of FTA then round down. So 5FTA is 2 shot equivalents because at least 1 of those FTA did was a part of a possession already accounted for.
Why use this?
It is easier than explaining that while James Harden may score 25 points and only shot 6/14 from the floor, he went 11/12 at the line so he was actually still very efficient scoring the ball despite shooting only 42% from the field. Instead of that you can do the math in your head and say he scored 25 points on 20 equivalents, and anyone can see that it is an efficient night. You could also of course substitute TS% in there, but then the math is not just super simple addition.
So yeah, that is what shot equivalents are. Now you know. Any further questions please put them here so I can answer them in one place.