For sports bettors, one of the joys – and challenges – of the football season is evaluating the teams and analyzing matchups, all in the hope of finding that elusive point spread winner.

There’s no shortage of statistics to sift through as witnessed by the dozens of football books and manuals on the shelves of the Gamblers Book Shop in Las Vegas, as well as a myriad of databases hawked by online sports services.

Many of the betting guides like to cite "trends" as some sort of road map to betting success. These trends are usually expressed as a team’s record against the spread (ATS), based on a set of parameters.

The parameters can be as simple as where a team plays (home vs. road), who it plays (conference or non-conference) when it plays (at night or in a dome), and so forth.

Trends can also be based on a complex set of parameters, often times uncorrelated and seemingly gleamed from an astrological chart: Here’s one for Oklahoma a couple of seasons ago: the Sooners are 1-2 ATS as a road favorite off back-to-back straight up wins versus an opponent off a double-digit straight up win.

Did you get all that?

A trend, by definition, is a "general course or prevailing tendency." Would that include the American League all-stars beating the National League all-stars for 13 straight years? If it would, the trend failed because this year the National League all-stars won.

On a simpler level, if you flipped a coin 10 times and it landed on heads all 10 times is that a trend? Does it somehow influence the chances on the 11th flip?

As an antithesis to trends is the "regression to the mean" theory, which stipulates that events tend to work their way back to the statistical average. Therefore, you should probably bet against heads on the 11th coin flip because in the long run, the coin should land evenly on heads or tails.

The problem with ATS trends is they’re based on the point spread. And, if the odds-maker is doing his job effectively (admittedly the "if" can be iffy), the theoretical result is a 50-50 proposition, like a coin flip.

For the most part, that has been the case as favorites in the NFL usually cover the spread 50 percent of the time, while favorites in the college ranks covered the spread slightly less than 50 percent.

So, if the point-spread outcome is virtually a coin flip, relying solely on it to predict the future outcome can be like rolling the dice.

For instance, take the New England Patriots in the 2007 season. They started out winning and covering their first eight games, which may have established in some bettors’ minds a solid ATS trend.

But in the 11 games that followed, the Patriots covered the spread only twice (including failing in eight of their last nine games), which probably meant disaster for many trend bettors.

A trendy approach from touts and sports services in recent years has been the "100 percent ATS" trend, which is supposed to be a can’t miss proposition.

Unfortunately, if you bet all the so-called 100 percent trends, you would have probably lost money.

Here are a few "100 percent trends" that didn’t live up to the hype, also from the 2007 season.

Northwestern was a solid 14-0 in games prior to the Michigan contest. But the streak was broken when they were blown out by Ohio State, 58-7.

BYU was 11-0 ATS as a dog in the first of back-to-back road games. That situation occurred at UCLA, but the Cougars lost and failed to cover the spread.

Nevada was 12-0 ATS when playing the second of back-to-back home games. That scenario unfolded twice that season, with the Wolf Pack going 1-1.

Oklahoma State was 11-0 ATS in games preceding Texas Tech. They were 11-1 after losing outright to Troy as a 10-point favorite.

Note that some of the 100 percent trends won, as you would expect when the outcome is theoretically 50-50.

But trends should always be viewed with caution, and they should never be used as a substitute for solid analysis, based on teams’ strengths and weaknesses.