Votes, that is. It's clear that a plug from the daytime diva can turn a book into a best seller (Anna Karenina & Love in the Time of Cholera increased 100% immediately after their selection into Oprah's Book Club). And she can turn any movie into a blockbuster. But academics are now asking if she can help decide the presidency?

This study of celebrity endorsements by two economists suggests yes. It claims that Oprah's plug was responsible for delivering approximately 1,000,000 additional votes to Obama, and secured his victory in the Primaries.

In the 45 state + DC sample size (the remaining states were those where Obama didn't appear on the ballot, or that don't report county-level voting information), Obama had 278,966 more votes than Clinton. Considering the study's 95% confidence interval (meaning they are 95% sure the number of votes Oprah contributed to Obama's campaign is in this interval), which is 423,123 to 1,596,995, Oprah's vote was responsible for the difference in the popular vote. Keep in mind, however, that this sample spread is much larger than the actual popular vote spread.

When she began her "political activist" career, Oprah told Larry King in an interview in May 2007, "My support of [Obama] is probably worth more than any check that I could write."

Indeed, it's worth 1,015,559 votes for Obama. A crude estimate shows that's 5.8% of the total 17,535,458 popular votes he received in the Democratic primaries.

Considering he spent about $270 million on the Primary campaign, her endorsement may be worth approximately $16 million. Yep, probably worth more than any check she would write.

Be sure to check out more of what Diana learned today here.