The Oakland Athletics, for weeks now, have been terrible. They’ve gone 27-37 in the season’s second half, with a 12-17 record in August and an even uglier 8-15 mark in September. Yet thanks largely to some atrocious play by their AL West rivals in Seattle, the A’s are about to clinch their third straight playoff berth anyway.Still, few people seem to be taking Oakland seriously as a World Series contender. Some of that disrespect comes from simple math: By having to play an additional one-game playoff just to get to the American League Division Series, the A’s face a tougher climb than MLB’s six division winners. But much of the disdain for Oakland’s chances stems from an overemphasis on momentum. If the A’s have stunk up the joint for most of August and September, why should anyone believe October will be any different?Because there’s no evidence to suggest that how a team plays heading into the postseason has any correlation with how it fares in the postseason. That’s why.Last week, we looked at teams’ regular-season road records and whether those can predict playoff success (the answer was yes, they do). Here, we used the same methodology, looking at every playoff game from 1969 through 2013 to see whether we could find a predictive link between late-season performance and playoff success.In the end, we found that full-season winning percentages were a significant predictor of postseason outcomes. But the degree to which a team was hot after June, July or August was not statistically significant when it came to forecasting playoff proficiency.Now that doesn’t necessarily prove definitively that there’s nothing to the momentum theory. As Bill James reminds us, an absence of evidence isn’t conclusive proof by itself, and it’s possible that further research using a different approach could yield different results.Still, given the hot-or-not narratives that pop up every October, and the lack of evidence to support the momentum theory, it’s probably time to take the A’s a bit more seriously as contenders. Jay Jaffe (at Baseball Prospectus) and Dave Cameron (for Fox Sports) both tested the theory by looking at playoff results from 1995 on and couldn’t find any statistically significant correlation either.Yes, the A’s will probably have to get past a stingy Kansas City Royals squad, one that’s excelled at pitching and defense all year, just to crack the ALDS. But with a pitching staff bolstered by the acquisitions of Jon Lester and Jeff Samardzija, and an offense that has struggled in the second half but looked strong in the first half, the A’s have the talent to compete for a title in a playoff field that lacks a clear favorite.As sharply as their luck turned down the stretch, it could just as easily turn for the better — starting now.CORRECTION (Sept. 26, 11:57 a.m.): A previous version of this article incorrectly said the Oakland Athletics have gone 27-39 in the season’s second half and had a 8-14 mark in September. They have gone 27-37 in the second half and 8-15 in September.