- Tuesday May 16th’s MLB Daily Betting Card features 9 MLB games
- 5 Main / 4 Runts
- Yesterday’s 05/15/23 Card resulted in a LOSS of -0.52 Unit Value on a 3-5 record. Almost back to having a winning day again.
- The full season 2023 MLB Betting Results is now at a Net Profit of +19.57 Unit Value with a 1.6% ROI.
May 16th, 2023 MLB Baseball Betting Cards details:
Ok, I admit yesterday’s brash changes were bad. I should never go for negative eROI plays even if the data suggests that based on past results. As I’m copping out in finding the true difference in WP% and riding the trend. I like trends as that’s the basis for the majority of my sports models. The hot hand should continue producing, until it doesn’t. But I need to fully understand why the WP% is wrong and adjust that and not run bets where the model says that the eROI is negative.
Forced Runts are gone, a failed experiment on a 1-3 record yesterday. But mostly due to their negative eROI that I was apprehensive about to begin with.
Looking at the 3 unit plays closer there really wasnt anything identifiable recently that I could say is the driver. The common theme was usually a late game blow up by a closer. Kenley Jansen had an amazing weekend in Boston after getting his 400th save, 😜. Reviewing bullpen stats for recent team performance, nothing stood out to me as suggesting trouble was a brewing in these games beforehand. Also I’m again apprehensive at adding more data sources to the model to create more work for an unknown payoff.
I decided to go back to the well of tweaking the unit sizes and the WP% with the data on hand.
Model 6.2:
There is no more Base Unit bonus. All games that meet the qualifying criteria will receive 1 Base unit for a bet.
Qualifying criteria:
- eROI > 3%
- BE ML < 64%. Best Odds for a pick have to be better than -180.
Picks can receive up to one additional Edge unit if the eROI is > 10%. Thus the maximum bet size is now limited to 2 units.
As usual Main card, favorites based on WP% > 50%, will get first attempt at qualifying for a bet if the Main pick is ineligible a Runt pick is attempted on that game if the criteria qualifies. Otherwise the game is scratched.
Lastly I decided to at least take advantage of one trend, one that’s so simple that most other bettors are already doing this in some form. I’m adjusting the WP% calculation for teams in my betting penalty box. Previously I would just reduce the unit sizes, but I’m going to penalize their WP% to make it more likely I place a bet against those teams and take advantage of their losing ways.
The bottom 2 teams, currently Oakland and Texas will get a 10% adjustment downward and the next bottom 3 will get an adjustment of 5% downward. The teams in the penaty box can be reviewed on my MLB Season stats page.
*See Glossary at bottom of page for details to help explain terms and other recent model changes.
*Final Results:
**I created a PGA Golf betting card for the AT&T Byron Nelson tournament this weekend. It just ended with Si Woo Kim being the only pick to place with a tie for 2nd in a Top 5 bet. The overall card resulted in a loss of 36% ROI.
___________________________________
___________________________________
Glossary of terms:
- Card: Denotes the reason for team selection
- Main: The main choice for a bet, criteria is any team favored to win a game with a >50% WP% and eROI >3%.
- Runts: Underdogs in terms of WP% that were selected as bets after the Favorite couldn’t be bet due to unfavorable odds (negative eROI after line shopping). Must be > 3% in terms of eROI for Runts card qualification, otherwise entire game is scratched from card.
- WP% = Win Probability %
- This is the key to my model, I source these typically from Fangraphs as they do a pretty accurate job based on backtesting of past data. I also add my own adjustments to make them more accurate. The data as a whole is accurate, but at a team level it has some variation. My adjustment adds or subtracts to the WP based on winning records of teams playing.
- ML Odds = The Moneyline odds that the sportsbook is offering for the bet
- BE ML = Breakeven Moneyline
- This is a calculation to convert the Moneyline into a percentage format to highlight how often the bet would have to win to show a breakeven in money won/loss on a bet with the given odds.
- eROI = expected Return on Investment
- This is the expected Return on Investment a bet would return overtime if we were able to consistently place a similar bet. The formula is WP/BE ML.
- For example a bet with an eROI of 10% would be expected to show a net profit of 10% over the true odds. If a bet had a WP = 50%, meaning it would win half the time, we would expect to show a profit of 10% on our bets if we won 5 and lost 5.
- Unit size terms = These are factors I’m using to determine the appropriate unit size to bet
- Base = 1 unit if qualifying. Qualifying is eROI>3% and BE ML < 64%.
- Edge= awards a bonus unit if eROI > 1%.
- Team = 1 unit penalty due to team being in bottom 5 of season profitability, can’t remove base unit.
May Adjustment
- I’ve alluded to the idea of adjusting unit values and the beginning of a given month seems an appropriate time for a 6 month season of baseball
- Entering May the bankroll for the season is up over 60 units.
- Assuming the initial bankroll to start the season was 100 Units that means so far the bankroll has increased over 60% and in order to see relative gains throughout the season we need to increase unit sizes.
- A safe measure of increase is 30%, about half of the gains so far this season.
- Going forward the Unit Values will be adjusted from $1 to $1.30
- The plan is to report all unit gains in terms of the orginal season starting value of $1, but know that the daily value of those units wagered going forward are now higher.
Model 6.1:
Return of L14 adjustor and introduction of Forced Runts, plays where Main card bets with eROI >10% are automatically forced to be Runt plays based on their overall performance YTD.
Model 6.0:
Two changes here, one to the units and one major change to the WP% calculation.
Units:
- Unit sizes will be reduced to have a maxium of 3 units.
- 1 Base unit for any qualifying bet where the picks has eROI% >3%
- A 2nd Base unit if the pick has WP% > 60%
- A 3rd possible unit if the eROI% > 10%
These unit changes should award only those bets where the WP% or eROI is large enough to be deserving. Then the swing between bets that barely meet qualifying criteria will only be 1-2 units of difference. This sould give every game some meaning and not be seen as a rounding error in the days final results.
WP% Adjustments:
- I made changes to the adjustment the other day by adding a 2% boost to Away calculations as it appears they are being undervalued by Fangraphs. They still are, but I’m going to go about the adjustment in a different way and to save some work.
- I’m removing the L14 adjustor as the results didn’t in the data showed a similar gap in accuracy to the unadjusted WP% straight from Fangraphs. This part takes a little bit of time each day to setup and calculate so removing it also removes extra work with no benefit on my part.
- The overall accuracy gap is on average off about 8% this resulted in about 16 more Away games won so far this season than a perfect WP% match would project. I’m adding a 5% multiplier to all Away probabilites going forward. So the WP% for Away teams will be multiplied by 1.05. Reviewing season results thus far with this change in place shows that the number of extra games won by Away teams compared to this adjusted WP% is only 0.5 games higher. Practically spot on.
- Now its obviously not guaranteed to hold, but it’s a good reset to get the model more aligned with actual results this season. The WP% will be monitored for any changes in accuracy going forward.
Model 5.5 Update:
Upon further review yesterday I noticed that with the success of Runts bets that I was overbetting Main bets. The problem was on the risk management side due to large bet sizes needed to win similar profits on these plays where the odds were skewed as heavy favorites typically.
I’m making a committment more to the value side of bets going forward and it means that the determination of unit sizes needed to be adjusted.
BASE: All picks will get 1 Base units as long as the eROI% is > 3%. If a pick is showing >60% on the WP% then 1 additional Base unit will be applied, giving Main Bets a max of 2 Base units possible and Runts a limit of 1.
EDGE: The minimum for a bet to be placed is an eROI% of > 3%, but the 1st edge unit will kick in at 5%. I might adjust this down the road, but for now Edge units are set to provide 1 Edge unit for every 5% interval up to a cap of 3 units or 15%+ eROI.
Model 5.4 adjustment:
Those damn Runts have surpassed Main card bets in profitability in just over a week on the scene. The issue appears to be not only credited to the Runts successful performance, but the Main cards underperformance. The Runts have saved what would be some even worse days without them. A closer examination at the Main bets is needed to identify the fault.
Accuracy of the Model:
Digging into the model it’s important to track the accuracy of the WP% as that is the driver which determines if a bet is Positive Expected Value (+EV/+eROI%).
The way I track accuracy is by comparing the data on hand for the season and block the WP% into bins of 5% intervals. I then compare the overall Win/Loss records of those bins to the expected Win % for that grouping to see if the performance is in line.
- The performance for Away Teams are overperforming their overall Bins by 15.5 games without the adjustor and by 16 games with the adjustor.
- This Away overperformance means that Away teams are winning more games than expected, the adjustor isn’t really making an impact here.
- The only way I see to correct this is to either let the season course correct or force in another adjustor factor. After 40+ days in the season I would say something is amiss this season for the MLB in regards to Away team performance. The one indicator I notice that Away Teams overperform is in Extra Innings. They have some sort of pychological edge here with the ghost runner, where they have the ability to jump out to a lead first, winning more than 50% of extra inning games. And this stat goes back to its implementation in 2020 not just this season.
- In addition I reviewed Fangraphs Splits for 2023 and there have been 41 Extra Inning games so far compared to just 26 by this same time in 2022.
- The larger number of Extra Inning games not only signals a benefit for the Away team, but also a sign of closer parity as teams are neck and neck forcing extras more often.
- Also something with the pitch clock and bigger bags could be forcing an issue that hasn’t been caught yet to benefit one side.
- I’ve decided that some factor is incorrect on the Fangraphs sourced WP% in regards to Away teams this season and I will be forcing a +2% adjustment to all Away Teams going forward. Immediately with this in effect it shifts the overperformance to only 6.6. It’s not a full correction, but that’s also because I’m unsure if the WP% advantage for Away teams will correct and this is only temporary. So this partial improvement should be a good test to see if accuracy improves and holds for the model going forward.
Banning of Breakeven (BE) odds > 64%/ -180:
Lastly I will be making one other model adjustment to continue the process of mitigating risk. All bets with BE odds >64% are now banned, meaning they will result in an automatic Runt selection or scratch. Reviewing my bets with odds >64% / -180 ML has shown about a 22 unit loss so far this season.
“The Juice is not worth the Squeeze” when it comes to these high odds plays that require significant invesment in unit sizes to see similar returns in regards to Runts play
Model 5.2 update:
Currently the Runts card has a 3% threshold in place for eROI and it just made sense to apply the same standards to the Main card picks.
The data I have on hand of bets made so far this season support this decision.
- Since the beginning of the season there have been 94 Main card picks with a sub 3% eROI. These picks have resulted in a net profit of 2 units.
- Going back to just April 12th there have been 57 such Main card picks resulting in a net loss of 22 units.
With this minor change it will have minimal impact on the overall picks produced each day, maybe throwing some more the Runts way and creating more profit. But overall it should be a small change that helps improve overall eROI as these low value plays are removed from consideration going forward.
Model 5.12:
The Team Penalty unit which currently deducts one unit off all eligible bets for a team if that team is currently in the bottom 5 of profitability on the season (See 2023 MLB Betting Results teams data). This list is dynamic as it changes each day, but going forward to prevent Oakland or any other future team from being a drain of underpeformance I’ve upped the penalty to 2 units for the last place team. Note that these penalties will never reduce bet size to less than 1 unit if the team is eligible for a bet.
The overall goal here is increase the volume of plays while reducing risk. As a result the finances of your bankroll should improve as the strategy should capitalize on postive ROI plays resulting in more overall units won/ profits in a faster timeframe.
Model 5.11 Update:
RUNTS card added. These are opposite picks of bets that failed to materialize for a certain team due to negative eROI. They are added if a targeted MAIN card favorite team doesn’t have a positve eROI after line shopping. The opposing team is then reviewed for a positive eROI of 3%+. If that is the case then the RUNT team is added as a bet and at a fixed unit size of 2.
A second minor change with Model 5.11 is that I added a Unit Reduction factor called Team. This is a flag of the bottom 5 teams in profitability that you can review each day in my 2023 MLB Seasons Results page. The idea is that these teams have already burned me quite a bit this year, so they will be penalized 1 unit so that I’m not stretching a bigger bet on teams that just have trouble winning when needed. This list is dynamic each day so the bottom 5 teams could be different if somehow these reduced bets or RUNT cards get these teams back in my good graces.
Model 5.0 Update:
Base Units needed to be recalibrated to allow 1 unit bets to return. Previous Model had 1 base unit for every 5% of Win Probability % (WP%) above 45%. Due to recent adjustments in the Model no bets under 50% were no longer being placed, so no bet of 1 unit was possible.
New Model scales up Base Unit floor to 50% on the WP% and allows up to 3 units for every level of 5% above it.
In addition a Bonus unit was added if both the Base Unit and Edge Units were each providing at least 2 Units apiece on a given bet. Meaning now up to 6 units is the new Max Unit size that is feasible.
For example, any bet where WP% >60% will provide 3 Base Units and containing an eROI > 10% will provide an additional 2 Edge Units and since both Unit sources are 2+ in size a bonus unit is added to give us a 6 unit bet .
______________________________
Don’t forget to check out the AT&T Byron Nelson event going on now. I provide a detailed step by step process on how I created the card and also includes a list of my top ranked players that I used to make the selections.
Also the Wells Fargo tournament last week was very rewarding. It had 4 hits in the top 10. The card ended up generating 124% ROI!
___
