Due to the way LinkedIn asks people about endorsing others, endorsers are usually people who are very kind to you, like your mom, your close friends, relatives.
Sure, there's a lot of noise in there. What I mean is that given enough endorsements, you kind of tend to get most endorsements in the skills you actually work with. It does not say much about how well you perform in those, but for searching out potential candidates, I imagine that it's fairly accurate.
