TRIPLE TIME (3rd right, Neil Callan) beats INSPIRAL (left) in The Queen Anne Stakes Royal Ascot 20 Jun 2023 - pic Steven Cargill /

Comparing Exacta and Computer Straight Forecast: Part 1

This article continues further research into ‘exotic’ bets, with the focus switching to predicting two horses to come first and second in a specific race, writes Dave Renham. As with the 1-2-3 trifecta and tricast bets, punters in the UK and Ireland have two options, namely the Exacta and the Computer Straight Forecast (CSF). The Exacta is a pool bet available with the Tote, while the CSF is a bookmaker bet that, like the tricast, has the payout/dividend calculated by a computer formula.

In this piece, I will compare the two to see if one is better than the other or at least one is better under certain circumstances.

With the Computer Straight Forecast, there is a method that you can use to estimate the likely payout for most races once you know the SPs. Essentially, you take the winner's price, add one point to the price of the second-placed horse, and multiply them together. Hence, in a race where the winner is 3/1 and the second is 5/1, you multiply 3 by 6 (5+1), and the forecast will pay around £18.00. Here are a couple of recent examples to help illustrate this. The first was a race at Windsor on 20th May:

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Using the estimating method, the payout should be around £48.00 (4 x 12), and as you see, the CSF paid £47.18. A second example comes from the same day at Carlisle:



This time, the rough payout calculation is around £25 (2.5 x 10), and once again, the estimate is within £1 of the actual payout, which was £25.79.

Therefore, as a punter we can have a relatively good idea of this potential payout pre-race if we leave our CSF bet as close to the ‘off’ as possible and by having the latest live bookie odds to hand. These odds should be very close to the actual SPs, so a quick calculation can help us decide whether we feel the probable odds justify the bet.

As far as predicting the likely payout of the exacta pre-race, one can often have a rough idea, too. This is because the Tote Pool Exacta Info can be accessed live on the net. However, they will only show the most popular exacta combinations, so you may not see your preferred combo in big fields. Being a pool bet, these dividends/potential payouts are continually changing. Still, when you get very close to the ‘off’, and if the pool is a decent size, any late changes in potential exacta dividend will be quite small. This is unless someone places a late exacta bet with a decent stake, which, fortunately, is quite rare. Like with the late placement idea of the CSF, late exacta placement is possible if your combination is shown on the Tote screen. If it is, then this gives you a decent prediction of the likely dividend to again help you decide whether the bet is value or not.

It's time to review some history. The data for this article has been taken from six months of UK and Irish racing spanning from 1st January 2023 to 30th June 2023. This includes National Hunt racing, All-Weather flat, and Turf Flat, with the proviso that races must have at least five runners. I have ignored any race with a dead heat for the first or second, as the payout gets split and messy.


Average Payouts (Overall)

First, let me compare the average payouts for the CSF and the Exacta from the six months of qualifying races, of which there were nearly 6000 in total. The figures are rounded to the nearest pound:



As with the trifecta/tricast research, the Tote bet, in this case, the Exacta, has come out on top. The Exacta ‘edge’ has averaged out to just above 19%, a significant difference.


Average Payouts by Race Code

I now want to look at the average payouts across the three race codes: National Hunt, All Weather Flat, and Turf Flat. Here are the splits:



The Exacta trumps the CSF in all three, but the edge has been less pronounced in all-weather racing. However, these initial findings suggest that the Exacta is a better value option than the CSF across all codes.


Race by Race Comparisons

Let me compare race by race, which came out ‘on top’ with the bigger return/payout more often. Races where the payout had a differential of less than 10 pence, I have called ‘ a draw’:



Having already seen the average payouts, these percentages will be no surprise. The difference is not as pronounced as we saw in the trifecta/tricast battle, but again, when taking a general view, the Exacta offers the better option.

Average Payouts UK v Ireland

I’m back comparing average payouts/dividends with a look now at UK average payouts versus Irish ones. Here are the figures:



As the figures show, the payouts have been much higher in Ireland. However, the main reason for this is Ireland's bigger average field size. The average number of runners in Ireland during these six months was 12, compared with an average of just 9 in the UK. Regarding the percentage edge to the Exacta versus the CSF, Irish races have seen a much more significant advantage using the Tote bet.

Average Payouts by Field Size

Sticking with the field size/number of runners angle, let's examine the average payouts for both bets to see if the Exacta edge increases as the field size does. I have split the results into the following field sizes: 5 to 7 runners, 8 to 10, 11 to 13, 14 to 16, and 17 or more. The blue line represents the Exacta and the orange line is the CSF:



The smallest field has just favoured the CSF, with the bookie’s bet having a slight 4% edge over the Exacta. However, this is the only ‘win’ for the CSF as the edge for the Exacta increases as the field size increases:



As you can see, the number of runners significantly impacted how the Exacta matched up with the CSF. There is a 32% edge for the Exacta when we get to 14-16 runner fields; once we go 17 or more, the edge is nudging 60%. Essentially, the bigger the field size the better as far as the Exacta is concerned. I, for one, will not be contemplating CSF bets instead of Exacta bets in races of 11 or more runners. I would be mad to do so based on these findings.

There were 233 qualifying races with 17 or more runners, of which the Exacta paid more than the CSF in 210–this equates to just over 90% of these races.

Average Payouts by Race Type

My next port of call is to examine the difference between handicaps and non-handicaps by comparing the average payouts/dividends of the two bets. Here are my findings:



Handicap payouts/dividends are higher for both, but in terms of Exacta's ‘edge’ over the CSF in handicaps vs non-handicaps, it is just 0.3% - essentially the same. However, to try and get greater insight, let me split the results down into more specific race types:



I had expected handicap hurdle races to show the most significant edge for the Exacta because these races tend to have bigger fields, but novice hurdle and chase races have edged it. National Hunt Flat races have seen the smallest edge for the Exacta over the CSF at only 5%.


Average Payout by Racecourse

For the last part of this first article, I will look at how the Exacta and CSF played out at different tracks. I will begin this section by sharing flat/AW courses with 40 or more qualifying races, giving us a good sample size. It includes all races, so a mix of handicaps and non-handicaps. Therefore, let me compare course by course, which of the two bets came out on top more often. I have listed the courses in alphabetical order:


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The six courses highlighted in red (Ascot, Bath, Gowran Park, Leopardstown, Musselburgh, and York) are those where the Exacta prevailed in at least 70% of races. Bath narrowly missed out by half a percent. The two courses in blue, Hamilton and Leicester, were the only two where the CSF beat the Exacta more often.

I'm sticking with Ascot because, with Royal Ascot just around the corner, I thought it would be interesting to look at the 2023 results to hopefully give us some pointers for the 2024 meeting. Here are the individual Exacta/CSF payouts for all 35 races (The rows in red are where the Exacta payout was bigger than the CSF one):



There were 31 wins out of 35 for the Exacta (88.5% of races), just three wins for the CSF and one ‘draw’. In 9 races (25.7% of races), the Exacta payout was at least double the CSF. 11 of the 12 handicaps (91.7% of races) saw the Exacta do best, of which 4 (33.3% of races) saw the Exacta paying more than double.

The average payout across all races for the Exacta was £400; for the CSF, it was £230. However, these averages were both badly skewed by the result of the first race on 22nd June, where a 150/1 shot prevailed. In that race, the CSF paid £3478.24; the Exacta £5369.6. Taking that race out, the average payouts over the other 34 races were – CSF £135 and Exacta £253.

The message is clear: if you plan to try and predict the first two home in a Royal Ascot race this year, the Exacta is by far the best option.

Moving away from the flat, let's review the same statistics for National Hunt course results (minimum 40 races):



Cheltenham is the only other track to have exceeded 70% for Exacta ‘wins’, while three have seen the CSF edge it: Fontwell, Ludlow, and Stratford.




It is time to wind up this first half of my comparison of Exacta and CSF, with more to come in a follow-up piece next time. At this juncture, Exacta is holding a healthy lead over the CSF. I expect that to continue next time, although I am currently still in the research phase of part two, so let's keep an open mind for now!


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4 replies
  1. Camira
    Camira says:

    Two points, well one is really a question.

    1. It is reasonable to EXPECT the Exacta to pay out higher dividends than the CSF. The greater the number of runners, the greater the difference that I would expect. This is because the Exacta (to my knowledge) takes a fixed % of the pool, whereas the CSF is based on SP % over-rounds which increase ‘semi-linearly’ with the number of runners.

    2. Where he favourite was odds on, from my experience in the trade, it was generally the case that SP % over-rounds were higher. This would also lead to the Exacta returning a higher dividend. Did DR look into this angle at all?

    • Dave Renham
      Dave Renham says:

      Camira – regarding the odds odd fav I haven’t not looked into that angle. When I have time I’ll see how easy it is to crunch that type of data. Hopefully I’ll be able to feedback something about that at some point. Dave

  2. Neil
    Neil says:

    I wonder if the CSF comes out on top if the top 2 or maybe 3 in the betting make up the payout , as I assume they would generally be most backed on exacta ?

    • Dave Renham
      Dave Renham says:

      In the second article I do look at the odds of the winners and the effect it has on both bets. I also look at favourite position too. cheers Dave

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