Thursday, 13 June 2019

Take The Money Or Run?

In baseball betting, the question of whether it is better to bet on the Run Line or the Money Line is often asked, including on my Twitter timeline yesterday.

It's the kind of question that keeps me awake at night. To clarify the difference, to win a bet on the Run Line, the favourite needs to win by two or more runs, or the underdog lose by fewer than two runs.

It shouldn't be a surprise that road (away) teams win a higher percentage of games on the Run Line than home teams, because if the home team takes a lead in the bottom of the ninth or an extra inning, the game is over.

The road team doesn't have the luxury of knowing what is required, and so they will keep trying to pad any lead.

The statistics show this quite clearly - from a robust sample size of 37,905 matches, the percentage of wins for road teams covering the Run Line is 75.4%, while for home teams, it is only 68.1%.

But of course, the market knows this, and the Run Line price is derived not only from the Money Line price, but also from the venue. 

The table below shows the approximate Run Line prices for some of the more common Money Lines, broken down by Home and Away and by league. 

The evens Run Line bet for a Home team falls around the PW = 0.675 mark, while for the Away team, it's around 0.62. 

But this chart is an average guide for MLB overall. The sharper minds among you are probably asking yourselves, "but isn't there a difference between the numbers for the two leagues?" and you would be correct. The Designated Hitter rule applied to games in American League ballparks, of course influences those numbers.

For example, the Run Line price on a -200 Money Line favourite (1.5) will average 2.087 if it is a National League team playing at home, to 1.8 if it is an American League team playing away. 

Then of course you need to look at whether they are playing away in a National League ballpark or an American League one. Averages only take you so far.  

One of the baseball ideas I've shared in this blog is the T-Bone system, and the results for Money Line and Run Line from 2011 to yesterday are:
Note that these profits are calculated based on risking the line to win one unit when playing on favorites, and risking one unit to win the line when playing on dogs.

While this is the basic system, it's always a good idea to look below the surface. For example, while most games are intra-league, since 1997 a number of games each season have been inter-league. From 214 games in that first season, the total has steadily increased so that since 2013, 300 games are now played, i.e. each team plays 20 such matches, the majority of which are played in June.

National League teams playing under American League rules have an ROI of -5.2%, while American League teams playing under National League rules are +2.0%.   

Looking at 'hotties', which have been a value bet since 2014, for home teams the ML ROI is 5.2%, while the RL 6.0%, but on the road, the percentages are both 9.9%

The public tends to favour home teams and be nervous of hot favourites in baseball, and other sports too, so the results aren't a huge surprise. That the inefficiency persists for so long, is.  

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