Barb, then I would suggest that "The Law of Large Numbers" may apply for people who don't know you…that there is some evidence in a large number of endorsements of a particular skill, but much more variability (lack of accuracy) in just a few endorsements. What it depends on, of course, is that there are enough accurate endorsements from enough people who really do know you to create some "accuracy".
… needless to say – it got me to thinking. Overall not a fan of the endorsement gaming that is running through linkedIN these days – but I wonder if Russ has a point. More investigation needed, because I KNOW it is not as simple as that 🙂