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NBA Projection Comparison

10/10/2006

Tis the season of NBA Player Projections. There are a bunch of sites posting their fantasy projections, either for free or as part of a subscription. But how can you tell if a set of projections is even worth the paper its printed on? Well, let's look a past performance...namely how well did each do in projecting the actual 2005-06 stats in each major category.

The Candidates

2004-05 Stats - the baseline. Any monkey could use the previous season's statistics. A good place to start.
2004-05 Post All-Star Break - a lot of people like to look at 2nd-half stats from the previous year.
NBA.com - free projections from their website
CBS Sportsline - free projections when you sign up for a team
Basketball Monster - Great website for rankings and managing your team. Projections were free last year. You need a $12 membership to get them this year.
Rotowire - pay for projections. You can buy these via the draft kit on yahoo for $15.
Wegoblogger - the projections I used for last year. You can get my current year projections here for free.

Note: if you have any other projections, let me know and I'll add them to the mix.

The Methodology

The projections for each category were compared to the actual 2005-06 statistics for 167 players that were common to each set of projections. 9 rookies were also included (but obviously not for the 2004-05 sets since they weren't in the NBA). For each of the 16 major categories (MIN,FGM,FGA,FG%, 3PM,3PA,3P%, FTM,FTA,FT%, REB,AST,STL,BLK,TO,PTS), the volatility of each of the projections was measured, and converted into a weighted-average standard deviation (essentially a +/- measure). Lower +/- means higher accuracy with the actual results.

The Results

MINUTES
Site Min
Wegoblogger31 4.557
Monster 4.565
0405All 4.950
0405Post 5.346
Rotowire 5.963
CBS -
NBA.Com -

Note: NBA.com and CBS did not have minute projections.

FIELD GOALS MADE
Site FGM
Wegoblogger31 1.111
Monster 1.118
0405All 1.184
Rotowire 1.261
0405Post 1.274
CBS 1.393
NBA.Com -

Note: NBA.com did not have FGM/FGA projections (only percentages).

FIELD GOALS ATTEMPTED
Site FGA
Monster 2.289
Wegoblogger31 2.290
0405All 2.419
0405Post 2.595
Rotowire 2.653
CBS 2.841
NBA.Com -


FIELD GOAL PERCENTAGE
Site FG%
Wegoblogger31 3.20%
NBA.Com 3.38%
Monster 3.42%
Rotowire 3.50%
CBS 3.51%
0405All 3.51%
0405Post 4.90%


THREE POINTERS MADE
Site 3PM
NBA.Com 0.386
Wegoblogger31 0.388
CBS 0.409
Monster 0.417
0405All 0.444
Rotowire 0.448
0405Post 0.466


THREE POINTERS ATTEMPTED
Site 3A
Wegoblogger31 0.928
Monster 0.987
CBS 0.990
0405Post 1.002
0405All 1.008
Rotowire 1.063
NBA.Com -

Note: NBA.com did not have 3PA or 3P% projections

THREE POINT PERCENTAGE
Site 3P%
Wegoblogger31 8.10%
CBS 8.90%
Rotowire 9.00%
0405All 9.17%
Monster 9.49%
0405Post 13.41%
NBA.Com -


FREE THROWS MADE
Site FTM
0405All 0.834
Wegoblogger31 0.855
Monster 0.886
Rotowire 0.905
0405Post 0.930
CBS 0.989
NBA.Com -

Note: NBA.Com did not have FTM and FTA projections (only percentages)

FREE THROWS ATTEMPTED
Site FTA
Wegoblogger31 1.031
0405All 1.056
Rotowire 1.078
Monster 1.095
0405Post 1.157
CBS 1.210
NBA.Com -


FREE THROW PERCENTAGE
Site FT%
NBA.Com 6.24%
CBS 6.35%
Wegoblogger31 6.48%
0405All 6.72%
Monster 6.73%
Rotowire 7.00%
0405Post 9.73%


REBOUNDS
Site REB
Wegoblogger31 1.215
Monster 1.219
0405All 1.226
CBS 1.247
NBA.Com 1.287
Rotowire 1.346
0405Post 1.438


ASSISTS
Site AST
Wegoblogger31 0.867
Monster 0.895
NBA.Com 0.935
0405All 0.967
Rotowire 1.027
0405Post 1.084
CBS 1.187


STEALS
Site STL
NBA.Com 0.286
Wegoblogger31 0.288
CBS 0.296
Monster 0.296
0405All 0.297
Rotowire 0.330
0405Post 0.344


BLOCKS
Site BLK
0405All 0.271
Wegoblogger31 0.297
Monster 0.298
NBA.Com 0.306
CBS 0.316
0405Post 0.333
Rotowire 0.338


TURNOVERS
Site TO
Wegoblogger31 0.427
Rotowire 0.434
0405All 0.443
NBA.Com 0.448
CBS 0.450
Monster 0.472
0405Post 0.534


POINTS
Site PTS
Wegoblogger31 2.962
Monster 2.963
0405All 3.115
0405Post 3.314
NBA.Com 3.330
Rotowire 3.363
CBS 3.747


So what does this all mean? Interestingly, using just the average BLK's and 3PM from 2004-05 would've been your best bet. NBA.com did well in FT%, 3PM, and STL. And I was surprised to see how poorly the post all-star break projections did across the board.

If we convert each category to an index where the 2004-05 stats equals 100, we can see how each projection did in the 9 roto categories.

Site FG% FT% 3M REB AS ST BK TO PTS AVG
Wegoblogger 91.2 96.5 87.5 99.1 89.6 97.1 109.4 96.4 95.1 95.8
Monster 97.3 100.2 93.9 99.5 92.5 99.6 109.9 106.5 95.1 99.4
NBA.Com 96.2 92.8 87.0 105.0 96.7 96.1 112.9 101.2 106.9 99.4
0405All 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0
CBS 100.0 94.6 92.2 101.8 122.7 99.6 116.3 101.6 120.3 105.4
Rotowire 99.6 104.2 100.9 109.8 106.2 110.9 124.3 98.0 108.0 106.9
0405Post 139.6 144.8 104.9 117.3 112.1 115.8 122.8 120.5 106.4 120.5

Using CBS Sportsline and Rotowire would've left you worse off than just using the previous year's statistics. My projections offered up a 5% improvement on average. Not trying to toot my own horn, but just showing that it's not too difficult to come up with a reasonable set of projections. Do your homework. Use mine, basketballmonster or nba.com as a starting point or just as a sanity check. If you see somebody who you think is ranked too low or too high, make sure there's some number you can point to that's causing you to think that (instead of just perception that player A is better than player B).

Perhaps even more critical is a projection's ability to identify those players whose statistics are most likely to change year over year (sleepers versus busts). This can be the deciding factor between victory and defeat. So if we look at the top 25 players that dropped or gained in each individual category, we can see how well each projection did in predicting that change. Again, 100 represents the baseline of 2004-05 (but since the players are ranked by their difference from the baseline, you'd expect most predictions to come below 100).

TOP 25 DROP
Top 25 Drop FG% FT% 3M REB AS ST BK TO PTS AVG
CBS 91.7 81.3 59.3 63.5 91.3 62.1 127.6 73.4 78.6 81.0
NBA.Com 90.8 87.7 75.3 75.2 80.2 70.2 138.5 68.1 85.3 85.7
Wegoblogger 94.4 100.6 75.8 83.9 81.8 78.8 140.4 68.3 90.6 90.5
0405Post 91.6 99.9 86.6 96.4 89.5 88.7 75.5 115.8 85.4 92.1
Monster 102.8 96.5 83.9 80.4 87.4 90.1 137.6 78.2 94.9 94.7
Rotowire 90.0 109.1 97.2 91.6 95.3 76.1 136.5 72.0 97.7 96.2
0405All 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0


TOP 25 GAIN
Top 25 Gain FG% FT% 3M REB AS ST BK TO PTS AVG
Wegoblogger 89.4 83.6 81.3 82.7 68.2 74.7 82.6 67.4 74.7 78.3
Rotowire 90.0 71.6 82.0 83.9 76.8 84.6 88.8 66.5 68.3 79.2
NBA.Com 97.0 80.4 91.0 90.2 78.6 87.9 106.8 68.6 95.9 88.5
Monster 90.0 98.1 94.9 82.8 85.8 94.8 85.1 86.2 80.2 88.6
0405All 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0
CBS 100.5 86.1 106.4 104.4 105.5 104.2 118.2 90.5 119.9 104.0
0405Post 87.5 115.4 100.9 110.2 106.5 115.6 124.2 111.4 91.2 107.0

The post all-star break numbers do show up as doing well in predicting those who might take a big dip in blocks the following year (much better than anything else), so there's one area where you might use it. My projections did a good job of capturing those with large increases and did okay with the decreases (other than blocks). Rotowire is probably not useful in anything other than identifying sleepers.

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