The draw bias at Chester racecourse, particularly over sprint distances, is a favourite example trend, simply because it is so pronounced when analyzed quantitatively.

Blindly backing any horse drawn in stall 1 and stall 2 in sprint races (defined as being over 5 and 6 furlongs) in larger fields (over 10 runners) has produced a consistent profit at starting price (and even more at Betfair SP) over the past few years.  Even in smaller fields and over longer distances, the first starting point for analyzing races at Chester should be the draw, though it’s always worth revisiting any assumption, especially when there is new information.

Last week at Chester, there were only 2 races qualifying with a larger number of runners (10+) over minimum distances.   For stalls drawn 1 and 2 these fared as follows:

+---------------------+----------------+-------+------+-------------+--------+
| scheduled_time      | winner         | stall | SP   | num_runners | result |
+---------------------+----------------+-------+------+-------------+--------+
| 2010-05-05 15:15:00 | Look Busy      |     2 | 9.00 |          13 |      4 |
| 2010-05-05 15:15:00 | Royal Intruder |     1 | 8.00 |          13 |      7 |
| 2010-05-06 16:30:00 | Tasmeem        |     1 | 9.00 |          11 |      5 |
| 2010-05-06 16:30:00 | Rule Of Nature |     2 | 3.00 |          11 |      2 |
+---------------------+----------------+-------+------+-------------+--------+

The best result any one of these could manage was second – and that was for the Michael Stoute trained Rule of Nature, which went off at a short price indeed and should have had a lot more going for its chances than the draw alone.

If we extend our survey to 7 furlong races, we find one more qualifier which produces a winner as follows:

+----------+---------------------+-----------------+-------+-------+-------------+--------+
| distance | scheduled_time      | winner          | stall | SP    | num_runners | result |
+----------+---------------------+-----------------+-------+-------+-------------+--------+
| 1100     | 2010-05-05 15:15:00 | Look Busy       | 2     | 9.00  | 13          | 4      |
| 1100     | 2010-05-05 15:15:00 | Royal Intruder  | 1     | 8.00  | 13          | 7      |
| 1320     | 2010-05-06 16:30:00 | Tasmeem         | 1     | 9.00  | 11          | 5      |
| 1320     | 2010-05-06 16:30:00 | Rule Of Nature  | 2     | 3.00  | 11          | 2      |
| 1540     | 2010-05-07 16:30:00 | Lucky Numbers   | 1     | 5.50  | 12          | 3      |
| 1540     | 2010-05-07 16:30:00 | Dance And Dance | 2     | 11.00 | 12          | 1      |
+----------+---------------------+-----------------+-------+-------+-------------+--------+


Just the one winner from the extra 7 furlong race produces sufficient returns, even at SP, to cover blind faith in the draw advantage alone, but clearly more analysis is needed, even at Chester.  Whilst it is obvious to anyone who has seen the Roodee that the draw advantage gives a significant edge to any runner racing on towards the inside rail, there are other factors as well as the draw at work to enable runners to get to the inside rail – and to secure that advantage.  Not least is the ability of a horse to break and lead early.  Whilst the effects of the draw are important, the proportion of front runners who win sprint races is equally compelling as we discuss in our analysis of front runners in this month’s Racing Ahead.  Combine a front runner at Chester with any stall position that gives it the ability to cross to the rail early, and you have a powerful combination to give that horse a winning edge – especially, in the case of stall position, if the horses drawn on the inside are less capable front runners.  So what did win the two larger field sprints at Chester last week?

+---------------------+-------------+-------+-------+-------------+--------+
| scheduled_time      | winner      | stall | SP    | num_runners | result |
+---------------------+-------------+-------+-------+-------------+--------+
| 2010-05-05 15:15:00 | Masamah     |     3 | 10.00 |          13 |      1 |
| 2010-05-06 16:30:00 | Horseradish |     6 |  3.75 |          11 |      1 |
+---------------------+-------------+-------+-------+-------------+--------+

Masamah still had an excellent draw in stall 3, a history of running from the front, and indeed ran as follows:
made all, ridden over 1f out, stayed on well final furlong

a running style that fits the hypothesis well.

In the case of Horseradish, he raced on softer ground than normal, and was able to track the leaders and still win, as follows:
tracked leaders, headway to lead over 1f out, ridden and stayed on well final furlong

Clearly relative ability will always enable horses to win races whatever their draw, though being drawn 6 of 11 on softer ground was not a huge disadvantage.

We’ll be using the Smartform database to produce more analyis of this sort over the coming months, which combines both in-running styles and draw analysis.