Alterations to the Flat Weight For Age Scale BHA Data Published 22 September 2016
Introduction What is weight for age? It is an allowance given to younger horses, usually three-year-olds, to enable them to compete equally with their older counterparts. It is designed to compensate them for their lack of physical maturity. How does it work? It is based on a theory of how the average horse develops. The scale makes the assumption that the longer the race, the more weight allowance a younger horse needs to compete equally. The allowance reduces as the year progresses and is linear as it is based on the assumption that the average horse develops at the same rate every half month. It is accepted that different animals develop at different rates some will be ahead of the scale, whilst others are behind it. How can we test the effectiveness of the Scale? The Weight For Age Scale should allow for a reasonable strike rate for both three-year-olds and for older horses when competing together. The strike rate should be consistent over different distances and months, and it should not unfairly advantage any particular age group. The following slides analyse the strike rate of three-year-olds against older horses in weight for age contests and handicaps over a period of 6 years (i.e. 2010 to 2015). We set out to investigate if there are any differences in the strike rate between each year, month and by distance category. The slides also capture the average winning distance of three-year-olds against older horses, and the Q&A section explains how we eliminated any possible variables that might affect the result. How big is the sample? A sample of over 8,000 handicaps and c. 600 weight for age races has been used, or more specifically 89,385 runners in handicaps and 5,136 runners in weight for age races. Races have only been selected if they are open to three-year-olds and upwards and have both generations participating in them. 2
Strike Rate & Average Winning Distance (split by age and year) Sample: 3yo+ Handicaps in 2010 to 2015 3yo runners 4,115 4,097 4,153 3,849 4,143 4,772 4yo+ runners 10,593 10,828 11,021 10,301 10,420 11,093 The strike rate (SR) for three-year-olds has been above that of older horses in each of the last six years. The average winning distance (AWD) of three-year-olds is about 0.2 lengths greater than for older horses. 3
Strike Rate & Average Winning Distance (split by age and month) Sample: 3yo+ Handicaps in 2010 to 2015 3yo runners 3,611 4,758 5,211 4,813 4,781 4yo+ runners 10,423 12,608 12,893 10,864 11,789 The increased three-year-old strike rate persists across all months, but it is most noticeable in July and August. Average winning distances for three-year-olds tend to be above those for older horses, apart from in November/December. NB: These two months have been combined because of their sample size. 4
Strike Rate & Average Winning Distance (split by age and distance) Sample: 3yo+ Handicaps in 2010 to 2015 3yo runners 2,666 4,391 4,377 4,942 1,088 3,224 474 2,417 252 1,298 4yo+ runners 8,866 12,491 10,753 11,436 2,450 6,740 970 5,651 704 4,195 The difference in strike rate between the two age groups is more evident over longer distances; it is particularly noticeable from 8f and above. From 10f and upwards, there is also an increase in the average winning distance for three-year-olds (around 0.5 lengths further than older horses). 5
Rivals Beaten an alternative to win only strike rate (split by age and month) Sample: 3yo+ Handicaps in 2010 to 2015 3yo runners 328 1,572 3,611 4,758 5,211 4,813 2,430 2,351 4yo+ runners 932 4,564 10,423 12,608 12,893 10,864 6,170 5,619 Rivals beaten is a different, yet still very robust, measure of strike rate because it takes account of the position of all horses in the field not just the winner. Please see the Q&A section on how this is calculated. From July onwards, three-year-olds consistently beat a greater proportion of the field than older horses. 6
Rivals Beaten an alternative to win only strike rate (split by age and distance) Sample: 3yo+ Handicaps in 2010 to 2015 Furlongs 3yo runners 2,666 4,391 4,377 4,942 1,088 3,224 474 2,417 252 1,298 4yo+ runners 8,866 12,491 10,753 11,436 2,450 6,740 970 5,651 704 4,195 There is a strong correlation between the proportion of the field that three-year-olds beat and the distance over which a race is run. From 8 furlongs and upwards, three-year-olds consistently beat more rivals on average than older horses (increasingly so as distance increases). The sample at 13 furlongs is quite small. 7
Summary - What does the analysis show? The strike rate for three-year-olds has been above that of older horses in each of the last six years. Strike Rate 2010 2011 2012 2013 2014 2015 3yo 10.8% 10.6% 12.4% 12.5% 12.4% 12.4% 4yo+ 8.9% 8.6% 8.0% 8.8% 9.1% 9.2% Variance 1.9% 2.0% 4.4% 3.8% 3.3% 3.2% Older horses have a relatively consistent strike rate of between 8% and 10% across all distances; whilst threeyear-olds have a higher strike rate, increasingly so as distance increases, and which is noticeably greater over 8 furlongs and above (at between 12% and 17%). Strike Rate 5f 6f 7f 8f 9f 10f 11f 12f 13f 14f+ 3yo 9.5% 9.9% 9.6% 11.8% 14.0% 12.9% 13.3% 16.2% 16.6% 17.2% 4yo+ 9.7% 8.7% 9.0% 8.8% 7.5% 8.7% 9.0% 7.9% 8.0% 7.8% Variance -0.2% 1.2% 0.6% 3.0% 6.5% 4.2% 4.3% 8.3% 8.6% 9.4% In addition to strike rate, there is also an increase in the average winning distances for three-year-olds (above and beyond that of older horses) from 10 furlongs and upwards. At shorter distances this amount precisely mirrors that of older horses. Winning Dist. 5f 6f 7f 8f 9f 10f 11f 12f 13f 14f+ 3yo 1.2 1.2 1.4 1.4 1.4 1.8 1.7 2.2 1.8 2.5 4yo+ 1.2 1.2 1.4 1.4 1.5 1.6 1.5 1.9 1.2 2.1 8
What changes are being made to the Scale, and when? The Weight For Age allowance for three-year-olds will be altered from 2017, with the first change coming into effect from the first half of June over 14 and 15 furlongs. Most other changes will be introduced from the first half of July over 10 furlongs and above. The alterations to the Scale range in size from -1lb at 10, 11 and 12 furlongs to a maximum decrease of 3lb over longer distances where the advantage afforded to three-year-olds was shown to be the most acute. In addition, changes to the four-year-old allowance between January and July, which naturally flow from the adjustments to the three-year-old allowance, will not come into effect until January 2018 (i.e. when the same pool of three-year-olds in 2017 ultimately turn four). Please see the next slide for a copy of the new Scale. 9
The New Scale Dist Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec (fur) Age 1-15 16-31 1-14 15-28 1-15 16-31 1-15 16-30 1-15 16-31 1-15 16-30 1-15 16-31 1-15 16-31 1-15 16-30 1-15 16-31 1-15 16-30 1-15 16-31 5 2 0 0 0 0 0 47 44 41 38 36 34 32 30 28 26 24 22 20 19 18 17 17 16 16 3 15 15 14 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1 0 0 0 0 0 0 6 2 0 0 0 0 0 0 0 0 44 41 38 36 33 31 28 26 24 22 21 20 19 18 17 17 3 16 16 15 15 14 13 12 11 10 9 8 7 6 5 4 3 2 2 1 1 0 0 0 0 7 2 0 0 0 0 0 0 0 0 0 0 0 0 38 35 32 30 27 25 23 22 21 20 19 19 3 18 18 17 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 2 1 1 0 0 8 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 37 34 31 28 26 24 23 22 21 20 3 20 20 19 19 18 17 15 14 13 12 11 10 9 8 7 6 5 4 3 3 2 2 1 1 9 3 22 22 21 21 20 19 17 15 14 13 12 11 10 9 8 7 6 5 4 4 3 3 2 2 4 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 3 23 23 22 22 21 20 19 17 15 14 13 12 10 9 8 7 6 5 4 4 3 3 2 2 4 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11 3 24 24 23 23 22 21 20 19 17 15 14 13 11 10 9 8 7 6 5 5 4 4 3 3 4 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12 3 25 25 24 24 23 22 21 20 19 17 15 14 12 11 10 9 8 7 6 6 5 5 4 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 3 26 26 25 25 24 23 22 21 20 19 17 15 13 11 10 9 8 7 6 6 5 5 4 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14 3 27 27 26 26 25 24 23 22 21 20 18 16 14 12 11 10 9 8 7 7 6 6 5 5 4 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 3 28 28 27 27 26 25 24 23 22 21 19 17 15 13 12 11 10 9 8 7 6 6 5 5 4 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 16 3 29 29 28 28 27 26 25 24 23 22 21 19 17 15 13 12 11 10 9 8 7 7 6 6 4 5 5 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 3 31 31 30 30 29 28 27 26 25 24 23 21 19 17 15 13 12 11 10 9 8 7 6 6 4 5 5 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20 3 33 33 32 32 31 30 29 28 27 26 25 23 21 19 17 15 13 12 11 10 9 8 7 7 4 6 6 5 5 4 4 3 3 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 Changes shown in orange will be introduced for 2017. Changes in blue affect the four-year-old allowance and won t be introduced until January 2018. 10
By how much has the Scale changed? Dist Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec (fur) Age 1-15 16-31 1-14 15-28 1-15 16-31 1-15 16-30 1-15 16-31 1-15 16-30 1-15 16-31 1-15 16-31 1-15 16-30 1-15 16-31 1-15 16-30 1-15 16-31 5 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 3 0 0 0 0 0 0 0 0 0 0 0 0-1 -1-1 -1-1 -1-1 -1-1 -1-1 -1 4-1 -1-1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11 3 0 0 0 0 0 0 0 0 0 0 0 0-1 -1-1 -1-1 -1-1 -1-1 -1-1 -1 4-1 -1-1 -1-1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12 3 0 0 0 0 0 0 0 0 0 0 0 0-1 -1-1 -1-1 -1-1 -1-1 -1-1 -1 4-1 -1-1 -1-1 -1-1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 3 0 0 0 0 0 0 0 0 0 0 0 0-1 -2-2 -2-2 -2-2 -2-2 -2-2 -2 4-2 -2-2 -2-2 -2-2 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 14 3 0 0 0 0 0 0 0 0 0 0-1 -1-1 -2-2 -2-2 -2-2 -2-2 -2-2 -2 4-2 -2-2 -2-2 -2-2 -1-1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 3 0 0 0 0 0 0 0 0 0 0-1 -2-2 -2-2 -2-2 -2-2 -2-2 -2-2 -2 4-2 -2-2 -2-2 -2-2 -2-2 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 16 3 0 0 0 0 0 0 0 0 0 0 0-1 -2-2 -2-2 -2-2 -2-2 -2-2 -2-2 4-2 -2-2 -2-2 -2-2 -2-2 -1-1 0 0 0 0 0 0 0 0 0 0 0 0 0 18 3 0 0 0 0 0 0 0 0 0 0 0-1 -2-3 -3-3 -2-2 -2-2 -2-3 -3-3 4-3 -3-3 -3-3 -3-3 -3-3 -2-2 -1 0 0 0 0 0 0 0 0 0 0 0 0 20 3 0 0 0 0 0 0 0 0 0 0 0-1 -2-3 -3-3 -3-2 -2-2 -2-3 -3-3 4-3 -3-3 -3-3 -3-3 -3-3 -2-2 -1-1 0 0 0 0 0 0 0 0 0 0 0 Changes shown in orange will be introduced for 2017. Changes in blue affect the four-year-old allowance and won t be introduced until January 2018. 11