There is no single way to do this and every punter, tipster and handicapper will have a different way to do it.
It could be argued that intrinsically you should never narrow down a field, as every horse entered in a race in theory has a winning chance but it is unrealistic and too time consuming to fully evaluate every horse in a 20+ runner race when we know the vast majority of the time certain horses are highly unlikely to win.
Around 85% of all races in Britain are won by a horse in the first 4 in the betting market, that’s a fact. True, this figure takes into account all the smaller field races with well fancied favourites and second-favourites, but it cannot be ignored.
One way to concentrate your efforts in big handicap races, but not the way, is to only include on your shortlist those who are the head of the betting market. This can at times be a dangerous practice as you may be ignoring an over-priced gem, but based on an average field size of 9 it means most winners are within the top 45% of the betting.
While it’s true we all want that 33/1 belter, in a 20-runner race you could be forgiven for concentrating on the first 8 or 9 in the market as there is around an 85% chance that the winner will come from there whether we like it or not. A 5/1 winner will always be better than a 33/1 loser so don’t let simple temptation get in the way of reality.
Using 10-year trends in big races is popular but be warned – it’s all rubbish! In recent times we’ve seen what were thought of as rock solid trends in the Grand National smashed to pieces, like ‘no French bred wins it’ or ‘no horse carrying more than 11st 5lbs has a chance’ etc.
Training techniques change, riders become fitter and more knowledgeable and much more importantly breeding trends change and these things all lead to very different results now compared to 20, 10 or even 5 years ago.
Ten-year trends on a race always provide skewed figures. For example in a top Flat race, you may see a comment that no three-year-old has won in the race in at least five years. What if no 3yo capable of winning was even entered in that time? It would be folly then to dismiss 3yo’s on that basis as what happened in the past does not have a direct bearing on what will happen in the future. Life itself has taught us that.
Learn To Predict Improvement
Improving horses win most races. Whether they are getting better short-term, i.e. coming back to form after some poor performances, or they are improvers overall because of age and experience which is the case for the vast majority of horses we need to learn how to predict that. Almost every thoroughbred will keep improving in the first part or even for the majority of their racing career.
If we are to narrow a field down to make it easier to judge, we need to cut out a combination of older, badly handicapped horses and those out of form (not over one race, but out of form for some time). These types will often be outsiders in the market anyway so unless you see money coming for them which could be as a result of them showing improved form at home you can often discount them.
Simplify Your Investigation
Think of your big race handicap as a criminal investigation. Starting off with 20 or 30 suspects makes this time consuming and difficult. By eliminating some of them, though only the ones you know not to have a chance, you are left with just a handful of possibilities meaning you could be dealing with a six-runner race but with big prices attached to them all.
From this point you’ll find it much easier to properly assess your short-listed candidates, evaluate their wants and needs in terms of racing conditions, and decipher which ones may improve more than the others and therefore outrun their handicap mark and their weight before coming to a fair, well thought out conclusion.