Comparing RotoEvil’s Rankings & Projections to Rotoworld and Basketball Monster
by Colin Christenen
Each year, serious fantasy basketball players visit countless websites, read numerous magazines, and pay for a few select fantasy basketball services to try to predict which players will be best in the upcoming year. And each year we win some leagues and lose others. It is rare, however, for there to be a systematic analysis of which sites did the best for projecting the best players for the upcoming year. Until now.
To find out which site did the best job of predicting player’s values, I compared the performance of a number of different sources for the 2012-2013 NBA season, for traditional 9-cat Roto leagues. I calculated the correlation for each source’s top 100 picks for 2012-13, with Basketball Monster’s full season top 100 at the end of the year on a per game basis.
The contenders were: RotoEvil (evl), Rotoworld’s top 100 from their draft guide (roto), Aaron Bruski of Rotoworld (bruski), Basketball Monster’s projected stats from last preseason (mns), Matt Buser of BBM (buser), the average of the expert’s valuation of the players’ values (exp2), average draft position (ADP), full season values from 2011-2012 (f12), second half values from the previous year (haf2), and full season values from 2010-2011 (f11).
We can establish a baseline by looking at how well last year’s stats correlate to the next year’s stats. A look at the chart reveals a correlation of .640 for last year’s stats to this year’s stats. Another way to establish a baseline is to look at ADP compared to end of season values. The ADP had a similar correlation of .645. If you are going to pay money for a fantasy website, make sure that they are beating the baseline of .645.
The clear winner for our contest was Eric Wong of RotoEvil. RotoEvil values correlated .729 with the end of season values. The closest anyone came to RotoEvil was Aaron Bruski with his correlation of .708.
Finishing a disappointing third place was Basketballmonster.com with a correlation of .686. Historically, they have usually done better in year’s past when I have done this exercise. Coming in fourth was Matt Buser with a correlation of .679. It will come as no surprise to readers of Rotoworld’s top 200 that their list came in the worst with a correlation of .653. Rotoworld is a great site and I read it on a daily basis, but their top 200 leaves much to be desired.
Nate Silver has made a splash of late with his prognosticating abilities. A big part of his approach is averaging the values for a number of polls and the opinion of experts to generate consensus picks. I used this approach as well when I generated an expert consensus value by averaging all of the expert’s opinions (exp2). The consensus values did very well with a correlation of .720 trailing only RotoEvil. This approach is certainly one to consider when generating your own values.
Thanks to all of our contestants for playing and congrats to RotoEvil for their win.
2013 evl bruski buser mns roto exp2 ADP f12 haf2 f11
evl 0.728519 1
bruski 0.708302 0.920246 1
buser 0.678858 0.940414 0.910215 1
mns 0.685977 0.925857 0.899178 0.954408 1
roto 0.653533 0.904888 0.879441 0.919089 0.868423 1
exp2 0.71956 0.971398 0.955334 0.980988 0.963354 0.94768 1
ADP 0.645426 0.909457 0.851626 0.95247 0.926179 0.929508 0.946629 1
f12 0.640299 0.878153 0.844798 0.875549 0.909078 0.826536 0.896941 0.881453 1
haf2 0.527414 0.80786 0.79914 0.814755 0.837641 0.775547 0.836172 0.803241 0.900586 1
f11 0.498715 0.683964 0.623978 0.65554 0.710662 0.617982 0.67478 0.708006 0.748338 0.655697 1
Eric is my basketball prophet. I’ve been in a money league with very competitive friends for about a decade now. Half of them use Basketball Monster, but when I added RotoEvil as my secret weapon in 2012 I had a competitive advantage. Eric’s perspective on how basketball talent and various circumstances translate into fantasy stats is unparalleled, because he understands the depths of basketball AS WELL as the maths of fantasy hoops.”
Thanks for the guide. I had been getting Rotoworld’s, but yours was a significant improvement, especially in your re-assessments of player values as draft day approached