Simple Projection System
"[I]t is the most basic forecasting system you can have, that uses as little intelligence as possible. So, that's the allusion to the monkey."
Let's see: basic, little intelligence, monkeys...I like it. I took Tom's general idea, tweaked it to apply to basketball and, presto, the SPS. Before I go through the methodology, let me state up front that I would not stake my reputation on these results. These projections are being published because (1) they were easy and (2) they were fun. That said, I do believe these results will hold up quite well when compared at the end of the season to other (and much more sophisticated) projection systems.
Now that the caveats are out of the way, let me walk you through the method, projecting Dwight Howard's 2008-09 rebounding as an example:
- Give the 2007-08 season a
weight of 6, the 2006-07 season a weight of 3, and the 2005-06 season a
weight of 1 and calculate the weighted sum of minutes played. The
previous three seasons Howard played 3088, 3023, 3021 minutes, so his
weighted sum is
6 * 3088 + 3 * 3023 + 1 * 3021 = 30618minutes played.
- Use the same weights as
above and calculate the weighted sum of rebounds. The previous
three seasons Howard grabbed 1161, 1008, and 1022 rebounds, so his
weighted sum is
6 * 1161 + 3 * 1008 + 1 * 1022 = 11012rebounds.
- Calculate the weighted sum
of rebounds for a league average player playing Howard's minutes, then
scale this figure to 1000 minutes. The weighted sum for a league
average player playing these minutes is
6 * 3088 * (103271 / 594100) + 3 * 3023 * (100994 / 595750) + 1 * 3021 * (100754 / 595550) = 5269.180rebounds. Scaled to 1000 minutes this is
1000 * (5269.180 / 30618) = 172.094rebounds.
- Calculate the player's
projected per-36 minute value. To do this we will find the sum of
(2) and (3); divide by the sum of (1) and 1000; and multiply by 36:
(11012 + 172.094) / (30618 + 1000) * 36 = 12.734rebounds per 36 minutes.
- Calculate and apply the age adjustment. If
the player is younger than 28, then the age adjustment is equal to
(28 - age) * 0.004. If the player is older than 28, then the adjustment is equal to
(28 - age) * 0.002. Howard's 2008-09 season was his age 23 season, so his age adjustment is
(28 - 23) * 0.004 = 0.02. Applying this to the figure in (4) we get
(1 + 0.02) * 12.734 = 13.0rebounds per 36 minutes.
A few more notes regarding the SPS:
- For the following categories the sign of the age adjustment is reversed: field goals missed, 3-point field goals missed, free throws missed, turnovers, and personal fouls.
- For the shooting categories, shots missed are projected rather than shots attempted. Projected shots attempted are then computed by adding projected shots made and projected shots missed.
- Projected points are computed using projected field goals made, projected 3-point field goals made, and projected free throws made.