Let’s see.

Iowa didn’t pick the eventual Republican nominee in 2012:

http://elections.nytimes.com/2012/primaries/states/iowa

Or in 2008:

http://politics.nytimes.com/election-guide/2008/results/states/IA.html

And did in 2004 only because Bush ran unopposed in the Republican party.

Not so sure Iowa’s results tell us much.