First, the Good News about winning the caucus in Iowa:
Since 1972, including Jimmy Carter’s 1976 second place finish behind uncommitted, the Democratic candidate receiving the highest percentage of votes in the Iowa caucus has gone on to win the nomination nine (9) out of 12 times.
At 75%, the results are pretty darn good at pointing to who will head the ticket.
It has produced the nominee in seven out of ten contested caucuses.
If you exclude the three caucus wins by incumbent Presidents seeking the nomination again, six out of nine is the record (66 and 2/3’s %).
If you exclude Carter’s 1975 second place behind uncommitted, and the three incumbents, it runs at at 55% for the winner becoming the the nominee.
Now for the not so Good News:
Since 1972, including Jimmy Carter’s 1976 second place finish behind uncommitted, the Democratic candidate receiving the highest percentage of votes in the Iowa caucus has gone on to win the general election four (4) out of 12 times (Carter in 1976, Clinton in 1996, Obama in 2008 and 20012).
At 33 and 1/3%, not so good.
Even worse when you look at the fact that two of those four wins were by incumbent Presidents (Clinton in 1996, Obama in 2012). It drops to 20%.
If you also exclude Carter’s second place finish in 1976, only one candidate winning the Democratic caucus in Iowa, who was not an incumbent President, has gone on to win the general election Obama in 2008).
Now you can argue a bit about whether Carter was the “winner” in 1976. It certainly was played like he won. He nonetheless finished behind the uncommitted.
The Republican winners of the caucus have done no better:
The only non-incumbent Republican to win the Iowa caucus and the presidency, since the ascendancy of the primary process determining the nominee, has been George W. Bush.
Excluding incumbent GOP Presidents, the caucus has picked the eventual nominee for that party approximately 45% of the time.
What is the predictive value of winning the Caucus:
Opinions will vary.
Admittedly, for this round I think you would rather be the winner than loser. In a close and crowded field, you may get the media bust to carry you forward.
It builds or help maintain momentum, will probably result in an influx of donations, media coverage.
In today’s 24/7 news world, it could drive the narrative, especially if it is a “surprise win”.
When the results are just slightly better than or worse than a coin flip for the nomination, it turns in into a “your guess is as good as mine”.
Do worse than expected, get shut out in delegates, or just eek out your lower tier percentage, the safe prediction your are in fact done.
Bottom line:
The predictive value of the caucus seems there is no real predictive value.
What Iowa has done historically is narrowing the field, or boosting a candidate with a better than expected finish.
As to winning be a road to victory, winning has not turned out well for most of either parties candidates.
If you believe in omens, jinxes, or just go with the stats, you might want to consider rooting for the other guy or woman.
(Listing of past winners of the Caucuses)