Should recent games count more?
Big Question
Do all games played in a season count the same, or should how a team is performing near the end of the season be given extra weight?
Easy Answer
Obviously, the easy answer is that all games have equal value.
Here, we argue that teams do not change or evolve from the beginning to the end of the season. After all, that's how we create conference and division standings and how we do tiebreakers, in leagues of all types all over the world. It's a simple philosophy.
Several of the computer ranking methods on "the list" follow this philosophy: Colley, Wilson, Rothman, ...
Giving Recent Games More Value
However, if you believe that teams do change as a season goes on, maybe you want to give more weight to recent games. The NCAA basketball committees used to do this by just simply looking at "record in the last 10 games," which is simple. But here, I'm talking about how something more quantitative, that applies to an entire season's worth of games. For example: at the end of a 12-game college football season, how much more important is the last regular season game, compared to the first? Twice as important? Three times? You need a mathematical formula, an equation, to do it.
My method: the game is weighted by how many days ago it was played, according to the formula
.
You can do the calculations for yourself, but by example, this means that on December 7, a college football game (or any game) played on September 1 is worth about 0.75 of a recent game. So they are all still highly-valued, but weighted just a little bit. Another example, like for the NBA: on April 15, a game played on November 6 would be worth 0.60 of a recent game. With many more games, you might argue that the early part of the season "has less value" since teams should evolve more over the course of a longer season.
Similar method: For college basketball, Bart Torvik (T-Rank) uses a similar method: "all games in the last 40 days count 100%, then degrade 1% per day until they're 80 days old, after which all games count 60%."
Other methods: [to be filled in]
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