Preseason football is one of the only places in which trends across several seasons can be meaningfully used.  The reason is that the winner of any game in the NFL Preseason is controlled almost entirely by which team is playing to win.  Which team wants to depends on just three things:
1.    The desire of the coach.
2.    The desire of the owner.
3.    The desire of the players when there is a battle for the starting or second string position. 

The intention of the coach or owner can vary from game to game or season to season, but some coaches and owners have shown that they always want to win.  Long-term trends can reveal those coaches, but the surest trends are usually those that are combined with a coaches general statements about his preseason philosophy.  Statements such as, “I believe teams need to establish a winning attitude in the Preseason,” or “I think the preseason is nothing more than a practice session against somebody other than your own guys,” can be very significant when couples with a long-term trend of preseason wins or losses that correspond with such statements. 

Preseason won-lost trends alone, however, should not be relied upon in a vacuum.  A change in circumstances can cause a coach or owner to change their attitude about winning preseason games.  . 

Bill Belichick, for example, always tried to win in the Preseason until his team won the Super Bowl.  The following year establishing a winning attitude in the preseason took a back seat to simply keeping the winning team healthy.  

An owner and coach with a poor record in the preseason may suddenly have a 4-0 preseason if ticket sales are slumping.  Thus, it is important to look at anything that might cause an coach’s attitude to change, or any statements indicating a change in attitude for the season or for a single game.

Reliance on short term trends and trends that are too limited should also be avoided.  In the game on Sunday, August 22, 2010 the Minnesota Vikings will be playing their second game of the Preseason at San Francisco.  Coming into the 2010 Preseason here’s something I read on the Internet:
It’s obvious that Childress does not care about the opening preseason game as he just goes thru the motions losing three of four openers as head coach. However he sure turns things around going all out in Week 2, seeing the Vikings go a perfect 4-0. So let’s fade them in Week 1 against the Rams, and make them a solid play in Week 2 against the 49ers.

The four-year trend is far too short to be meaningful, and far too limited to indicate a general coaching attitude.  This year, in Week 1, the Vikings trounced their opponent by a score of 28-7, and didn’t look at all like they didn’t care.  There is usually a gentleman’s agreement in the preseason that the teams will not go after their opponent’s quarterback.  Teams that don’t care about winning will stick to this agreement by avoiding the blitz.  In Week 1, Minnesota sacked the QB an amazing six times.  That’s not exactly a sign of a team that isn’t trying. 

Now that Coach Childress has broken his string of losses in Week 1, will he flip flop the other way and lose the game in Week 2?  It’s impossible to say, but you certainly can’t rely on the 4-0 Week 2 trend after the obvious failure of the 0-4 Week 1 trend.

Coach Childress has said nothing about his intentions in Week 2 and there is nothing apparent to cause a change in the coaching attitude.  The only conclusion that can be drawn from the 0-4 record in the first Preseason game and the win this year is that the 0-4 did not reflect any particular coaching attitude in the first place and was no more meaningful than red appearing four times in a row on roulette wheel. 

Statistically, with four preseason games each year, the odds of one of the games showing four wins or four losses are 3-1 against.  In other words one of the four games should always be at 4-0, and it is not that strange to find two 4-0 streaks at the same time without there being any particular reason for it.

The 4-0 Week 2 trend is meaningless without something more to support it. 

To get the total on tonight’s game for only $10.00 click HERE.  /pregamepros/pro-bettor/bettor.aspx?id=4441#capper