Oddly, Wonderlic scores have never been proven to have any positive link with future on-field performance. In fact, one study[1] actually found a negative correlation at some positions.

But as with many silly personnel evaluation techniques that are in common use, general managers will never get punished for doing what everyone else is doing.

[1]: http://www.tandfonline.com/doi/abs/10.1080/08959280902970401