The growth of statistical analysis in fantasy football has been incredible to watch as numerous web sites dig into some pretty in-depth metrics for you to study when analyzing the performance of both NFL teams and their players. However, as pointed out in the Stats You Need to Know series, there are some pitfalls you can fall into when looking at year-to-year numbers. Things change at a rapid rate in the NFL. Not only is player movement abundant, but the revolving doors we’ve seen for head coaches and both offensive and defensive coordinators seem to be in a perpetual spin.

As a result, comparing performances between the different seasons can often be an exercise in futility. A running back who found success against a particular team one year cannot be guaranteed success the following season as, not only could the opposition change defensive coordinators and systems, but said running back’s team could have gone through its own changes as well. Or, that player could be on an...