Fantasy baseball brings out the competitive bastard in me. Expert leagues, NFBC, and DFS sites like DraftKings are the standard targets of my affliction but I also get obsessive about our daily projections. Short of maybe gambling and winning big bucks in DFS (not going to happen with my limited risk tolerance), it is hard to find ways to test the quality of our daily projections.

It is not for lack of trying. I compare our DFS hitter and pitcher point projections against DFS site salaries in our DFSBot on our Ombotsman page and – going back to May 2014 – there has yet to be a month where a DFS site’s salary has outperformed us. I did a 2 month test last year against ESPN Fantasy Forecaster that showed our starting pitcher projections were superior. I tested last year’s projections against hitter and pitcher recent game data to find areas that could use improvement (highlighted pitcher IP should leverage recent starts more).

As I was contemplating new targets to compare against, I was IM’ing with our lead DFS writer (Sky) and he noted that he looks at Vegas Over/Under estimates for Runs when considering teams to stack. That got me thinking…I could go for some pancakes. After eating those pancakes, I thought, “What if I test our projections against Vegas!”. Then I napped.

Yada yada yada, below are the (favorable) test results versus Las Vegas MLB lines. See bottom of post for some testing notes. As an added bonus (until someone pays me to take them down), DFS Premium subscribers can see these team run projections updated every day (for today + at least the next 6 days) on our Teamonator page.

Please visit our Subscription page for more information on our daily projection subscription packages. We offer daily, monthly, and season long packages – catering both to the Roto and DFS player (if you play both, even better).

Also, stay tuned tomorrow for an awesome addition to DFSBot!!!

Games Included: 169 Non-Double Header Games (338 GS) between May 26th and June 7th
Razzball Opposing Team ERA Projection Vegas Team Run Projection Razzball Hitter Run Projection Razzball Hitter RBI Projection
Average 3.860 3.818 3.966 3.920
Correlation to Team Runs (r) 0.231 0.195 0.205 0.168 0.182
AAE to Team Runs 2.067 2.099 2.092 2.120 2.104

Summary: Razzball ERA projections (for the opposing team) had both a higher correlation and a lower average absolute error to a team’s runs scored than Vegas’ team run projection. This difference is not statistically significant based on this sample size but it is a very good sign that our projections are at least statistically comparable to Vegas. As for the R/RBI projections, they are slightly worse but with the same statistical significance caveats.


Games Included: 169 Non-Double Header Games (338 GS) between May 26th and June7th
Razzball Both Team ERA Projections Vegas O/U Razzball Total Hitter Run Projection Razzball Total Hitter RBI Projection
Average 7.719 7.637 7.932 7.840
Correlation to Team Runs (r) 0.240 0.238 0.200 0.222
AAE to Team Runs 2.937 2.949 2.960 2.944

Summary: Same general story as with Team Runs – our ERA projections slightly ahead of Vegas for the test but not statistically significant. Positive sign nonetheless!


Picking Winners (% of Time The Team w/ More Projected Runs or Vegas Odds-on Favorite Won)
Razzball ERA Vegas Line Razzball Total Hitter Run Projection Razzball Total Hitter RBI Projection
Winning % 57.4% 52.4% 52.1% 50.9%

Summary: This is a surprising one. The average ‘favorite’ for Vegas was 55.7% but they only won 52.4% of the time meaning there was a slight run on underdogs during the test (netting out to a yawn-inducing 1.8% ROI if you invested in every underdog). The average ERA favorite was only about 53% – I am chalking the difference vs the 57.4% to some good luck. But, again, still a positive sign that our projections are comparable in quality to Vegas.


Test Notes:

  • Since my projections are made before lineups are announced, I estimate a percent chance for each hitter to start (%Start). For Team Run/RBI totals, I summed Runs, RBIs, and ‘%Start’ estimates. I then multiplied each team’s Run and RBI totals by the Sum of % Start / 8.59. So teams where I overprojected playing time have their Runs/RBIs brought down and vice versa.
  • The Hitter Run and RBI totals correlate (r) at 0.906 and 0.867 with the ERA projections. Reasons for differences include: 1) Caught a bug in my archiving of R/RBI projections that did not update if I re-ran during the day based on starting pitcher chance or hitter activation/DL, 2) ERA doesn’t account for unearned runs, 3) There are R instances without RBIs, and 4) While all three projections use the same park factors, they are calculated independently based on Steamer ROS ERA and Steamer R/RBI to batting event ratios. To get these three stats to optimally align (prior to posted lineups) would require a megaton of development at very minor gain. Still TBD how much re-running against posted lineups would improve accuracy.
  • I used for Vegas lines and O/U. To estimate Vegas team run projections, I did the following calculation: Underdog Runs = 100/(Line+100)*O/U run projection. Favorite equals O/U minus Underdog runs.  -3.15224+5.43206*Vegas projected win % + 0.550223*O/U runs. This calculation was based on a regression of various scores and their Pythagorean Winning Percentage.
2020 Draft Kit
  1. J-FOH says:

    So what you’re saying is whenever I go to Vegas I need to take you with me for gambling advice?

      • J-FOH says:

        @Rudy Gamble: sorry I didn’t write my pun correctly, for gamble-ing advice, and fine I’ll take Grey and his 8th grade tolerance for alcohol.

        • @J-FOH: Ha – I razzed him about his tolerance in my best man speech. Ah…Gamble…gambling….pun now understood

          • J-FOH says:

            @Rudy Gamble: funny thing is he doesnt change much sober to drunk when dealing with people

  2. The Great Knoche says:

    Great info. Love the numbers.

    Also they aren’t going to pay you to take it down. A Joe Pesci looking guy with a guy who look like J-FOH, but in a suit will just show up and suggest you take it down.

  3. pbmax says:

    Streamanator is my favorite! Thank you for all the fine work you do Rudy and Grey and the Razzball team

  4. evo34 says:

    “To estimates Vegas team run projections, I did the following calculation: Underdog Runs = 100/(Line+100)*O/U run projection. ”

    Whoa. That’s not even close to being accurate. Being projected to win 33% of the time (+200 odds) does not mean a team is projected to score 33% of the runs. You need to develop (Goolgle) an equation to convert vig-neutral totals and money line odds to median indiv. team runs projections. That, or find a source of historical team totals (with vig) and compare directly.

    • Thanks. I had Googled and that was the formula I found for converting runs. I will retest if another formula is presented. I ran the test on total runs as well and the results are similar.

    • @evo34: Okay, dug deeper and you are totally right. I ran a regression on a number of Run scored/Runs Against scores and the Pythagorean % chance of winning (RS^2/(RS^2+RA^2). Corrections made in the article.

      The new formula did produce marginally better results than the incorrect way I calculated the runs per team but it still fell below our results.

      Thanks for the feedback!

  5. MattTruss

    MattTruss says:

    Welp, you just made my day Rudy! This is awesome stuff. Before long I’m never going to need to leave for anything!

  6. Chris says:

    Hey Rudy Thanks for the info!

    What are your thoughts on Rusin SP for Colorado and would you drop Brad Miller for him. I’m in a 5×5 h2h roto, my MI is LeMahieu-Perlata-Panik-A Escobar and I could use the pitching. Also just picked up Jungman. Thoughts?


  7. mcBlunty says:

    Taiwan Walker or Eric Hosmer?

    • @mcBlunty: I think Walker is the better pitcher but Hosmer has a much better bat. I’d take Hosmer’s bat over Walker’s arm.

  8. Spammer Jay says:

    Rudy, give this one to Grey for tomorrow AM. ‘Hesto Presto!’

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