Summer Mile

Continuing my race simulation analyses, I am this weekend looking at the Summer Mile at Ascot. As I have with other races (see here and here for recent examples), I simulated 100,000 renewals by using recent (2018 on) RPR data from the runners as a means of predicting how likely they are to achieve a certain RPR (and win, or place, in each simulation).

Thankfully the majority of the runners have a relatively comprehensive back-history of running in Graded/Group/Listed company and a lot of RPR data to work with, which means this should be a relatively good race to perform this sort of analysis on.

Data and Method

I used exactly the same base method as described previously (see the Queen Anne post for more detailed information). More briefly, I:

  • Recorded the RPR average (mean) and standard deviation (a measure of the variation around the mean) of all horses from turf Group/Graded/Listed races in 2018 and 2019
  • Computed 100,000 potential RPRs for each horse by using the analysis software, R, and a “truncated” normal distribution algorithm (with the lower limits set at a possible RPR of 0 and the upper at 3lb above each horses’ highest recent RPR) — see Figure below to visualise this process
  • Ranked horses from highest RPR to lowest in each of the 100,000 simulated renewals and then calculate the proportion of these that each horse won (highest RPR) and placed in (highest three RPRs)
  • Computed “fair” win and place odds for each horse based on these proportions

In the above figure you can see the probability of Matterhorn running to a specific RPR in the Summer Mile (grey bars and curve), along with Beat The Bank (royal blue curve); Accidental Agent (light blue curve); Suedois (red curve); Tip Two Win (black curve); Wadilsafa (blue curve); Zaaki (yellow curve); Awesometank (green curve).


According to the simulations this is a more open race than the bookmakers’ odds would imply, with Matterhorn favourite at just under 4-1 (4.9).—see Table below.





Fair Win Odds


Fair Place Odds

Beat The Bank 9.6 3.8
Accidental Agent 6.8 2.7
Matterhorn 4.9 1.36
Suedois 5.7 2.04
Tip Two Win 9.9 3.8
Wadilsafa 10.1 3.5
Zaaki 6.4 2.1
Awesometank 78 8.3


There are a number of additional points of note. These include:

  • Beat The Bank being a good bit bigger according to the simulations than with the bookmakers – this is down to his inconsistency, as he has returned a few very poor RPRs among the very good ones (see limitations below)
  • Each horse’s fair win odds only correlate relatively closely with their fair place odds R2 = 0.86, or 86%); the notable anomaly being: Matterhorn (who only has the potential and ability to run race-winning RPRs relatively frequently given his consistency, which suggests he has an outstanding chance of hitting the frame)


RPRs are a relatively solid way of assessing a horse’s ability based on past performances, but there are examples when you should be less confident in their use than others.

Beat The Bank seems to be a bigger price than I would have expected based on his ability to hit the frame and to win the race. This is due to the simulations weighting his poor runs (low RPRs) equally when compared with his better ones. That is of course fair, but I suspect he is less likely to run a poor RPR in this company compared to the more competitive Grade Ones that have occasionally seen him run disappointingly. As a result, I am wary of taking his “fair win” and “fair place” odds too literally here, and expect he has a much better chance than they imply.

Accidental Agent refused to race last time, which presented a huge challenge regarding how to feed that into the simulation. I eventually decided to give him a pass – rather than entering a 0 – as I felt the latter option would have skewed his odds unrepresentatively when taking his ability into account. Naturally, I would be wary of backing him based on that latest misdemeanour.

Advised bet(s) and staking plans

I am trialling this simulation method from a punting point of view, and am tracking advised bets via a:

a) Points-based staking plan (based on the perceived value available — see here for more info) beginning at a P&L of 0

b) Conservative (1/4) Kelly Criterion statistic(see here for more info) beginning with a fictional bank of 1000 euro

For the Summer Mile, the bets will be:

a) 2 pts Place Matterhorn at 2.2 (6-5) with Coral/Sky Bet as of 11:40 am, Saturday July 13 

b) 143.15 euro Place Matterhorn (1/4 Kelly Criterion = 13.08% of bank)

Future Directions 

I will be using this technique to produce “fair odds” for Hong Kong racing beginning next season. HK fare is appealing for this type of analysis as there is a huge amount of ultra-reliable data available to work with.

I plan to produce my own sectional-enhanced speed ratings for all horses running in HK and use these instead of RPRs to model “fair odds” ahead of many of the meetings.

I may also look to trial it on the AW in the UK over the winter, as sectional times should be easy to calculate thanks to what is now available from certain tracks on the At The Races website.

Watch this space.