I’d hardly call it luck, considering that he called the last two presidential elections correctly (hitting 50 of 50 in the latest) and projected a significant Republican gain in the last mid-terms.
He called them correctly. HOWEVER, his probability for an 0bama win was >90%. There is NO WAY to prove that it wasn’t, say, 70%.
However, his model has been fairly accurate (more accurate than most) at calling many races across the country.