I have a question for the forum regarding a NFL model I'm currently working on. I just backtested my model on the 2008 season.
For the 2008 season vegas chalk from week 4 and out went 67.22%. My model went 63.40%. However, with my model the percentage that it gives a team winning is on the spot. Teams in the 50-59% bin win around 55% of the time, teams in the 60-69% bin win around 65%, etc.
I then took a look real quick to see how my line did vs vegas' line by looking at vegas dogs my model said should be favored. When this situation arose my plays went 23-31 su (42.6%). I also did some real quick eyeballing of games where my model gave teams a big time win% edge and the vegas line was quite small. Say last year's dallas at phila game to end the year. Phila was a 80%+ su winner according to my model. Vegas said they were small chalk. Phila crushed them. There were other games like this, as well. Then there were games were the chalk was too heavy and my model liked the dog. The dogs came in with the pts as winners.
With that said I'll now get to my question. Is this one year test enough? If not how many would be?
*As a note, the model I put together knew nothing of how the 2008 season data would turn out. All the data my model is based off is taken from previous games in past seasons.