Sometimes the ordinary punter is mystified by things that really should be second nature. One of those is the matter of weights in racing.

Weight for age is only a name. Don't be frightened by it. It's there to help us. It means that there is a set scale, for any month of the year, for any aged horse. A scale that will enable the punter, or bookmaker, or handicapper, to assess one horse against another.

This is regardless of the abilities of the horses concerned. There is no heed taken of the class, the form, the previous records, the opinions of writers or trainers, in fact nothing. Just a scale of weights so that comparison can be made.

However, although we say there are no comparisons of this sort, the scale itself imposes the comparisons. This is because the better horses have the advantage when they meet the weaker ones at fair weights.

If, for example, a top-class colt is carrying 53 kilograms in a 1200 metres handicap race in February, we say he is carrying weight for age. This is because 53 kilos (8st 51b in the old language) is the two hundred year old established weight for a three-year-old male, six months into his three-year-old season, at that distance.

We should not confuse this with the set weights that three year olds might carry in races against each other. For example, the derby may require them all to carry 57kg, but that is against each other. They are carrying a traditional weight (the same as the various derbies around the world) but actually more than weight for age.

Going back to the example of the colt carrying 53, let us say that there are six good chances in that race and he is one of them. Say there are three four year olds, a five year old and a six year old that also have good chances.

The weight for age scale for February (this scale is printed regularly in your weekend form guides) is as follows:

3yo      4yo     5yo and above
53kg    57kg    57.5kg

And so there are four kilos between our three year old and the four year olds, and another half kilo to the older horses. By May the three year old will be up to 55 and the others all on 57. So you see the scale assumes that the peak age is probably early five, although at late five and over he is still asked to carry more weight in distance races.

Horses are usually still developing until they are late four, even five or more. A lot of 'chasers don't really fill out until they are seven or eight.

So, if our horse has 'weight for age' in a handicap event, and those other chances have more than the 'correct' weight, then you could say that our horse has an advantage. More on that later.

Some believe that early in the three year old's season is his best chance, as he receives a lot of weight from the rest of the runners. For example, in November, using the Melbourne Cup distance, 'weight for age' weight for a three year old would be 48.5kg, getting 8.5 kilos from four year olds and 9.5 kilos from older horses. If he is a strong young horse he may try his luck in big events, as he will never receive such luxury weights again.

This is why, with his feather weight of 47 kilos, owner Tom Smith was so keen for Nothin' Leica Dane to run in last year's Melbourne Cup. Nothin' Leica Dane was 1.5kg under the scale, in form and strong. Very immature, true, but he would never get the chance like that again after winning the VRC Derby.

However, the other school of thought is that weight for age is a genuine guide, can only be used to match one horse against the others, and it is one of the very few things in racing that has withstood virtually all tampering and adjustment. Take a look at how some other weights were distributed in the Melbourne Cup.

Jeune had 59 (weight for age for a horse his age), as did Vintage Crop (who might have won and certainly should have beaten Nothin' Leica Dane), while the much-vaunted Double Trigger (remember him?) came in with 60.5, or one and a half over the scale.

But Doriemus, with 54.5, winner of the Caulfield Cup, was actually in 4.5kg under the scale, much better than Nothin' Leica Dane, and this was after a three kilo penalty for the Caulfield Cup. That penalty was as big as any handed down in recent times and gave a specific hint that the handicapper wanted to get at this bloke again.

Imagine what a bet he was if he had not had the penalty!

He'd have been 7.5 kilos under the scale.

Although Nothin' Leica Dane ran a brave second, he was demolished by a more advantaged 'weight horse'.

I feel that the ordinary punter can win money more easily on handicaps. How come? In case you forgot, the Melbourne Cup is a handicap, even though we were talking about weight for age and relative advantages.

In a true weight for age race there are no such advantages. They get what they get, like the computer term wysiwyg ("what you see is what you get"). In a handicap, it's all there for the considering, the weighing up in fact.

What we have been building up to here is the use of the weight for age scale to assess horses' chances in NON weight for age races. It is the best guide we can ever get from the man who has to get things right, the handicapper.

A fundamental question here is in order. Is it better to be near the bottom of the weights or the top?

The novice would say "bottom". Of course it looks that way. The less weight a good horse has to carry, the better its chances.

Maybe. Think about this though:

The thing that really matters in a handicap is the relative weight. If a horse is carrying 58kg in a 53 limit race (the limit is always listed for you in your raceguide), he is five kilos over the limit. Let us say he is a five year old racing at 1600 metres in February.

This means he has weight for age, since when you look up the charts you'll find that weight for age for a five year old male at 1600 metres in February is 58 kilos. So he has five above the limit and is racing at his weight for age weight.

Now let's assume that there are four three year olds in the race and no claims are allowable. The weight for age figure for them at that time of the year is 52, so they all have to carry over weight for age, regardless of what the handicapper thinks of them!

All right, let's assume there are five four year olds and two other five year olds to make up the field. The four year olds would have 57 kilos at weight for age, so we check to see if any of them has less. If so, we have found our first horse that is 'favourably treated' under the scale. If either of the five year olds has less than 58, he too is better off than our horse.

A small point here. Mares and fillies get an allowance, so I am using only males in order not to complicate things. Another point: four year olds are easiest as they are the same weight (57) all year, the international standard benchmark nine stone.

Needless to say, winning is not just a simple matter of establishing the advantages one horse has over another in the matter of weight for age, but it is a factor often overlooked and it can tell you a lot about the chances. It's easy too, and once you get the hang of it you don't have to keep making checks.

The key factor can be the weight carried over the limit, and not the relative weights carried. That is why I put the question about being near the top or the bottom of the weights. Let's think about this one.

Say that in November there is a 2400 metres field going around, and it has five good chances, five horses who are reasonably equal in ability on everything they have ever shown. Now say that four of those five 'equal chances' are three years old and one is a six year old. Say he has 56kg and they all have less, on a 52 kilos limit. He is four over the limit but he is also three kilos under weight for age.

The fact is that he is going to have an advantage, regardless of what weights the three year olds have, even if they have three kilo apprentices claiming! The best any of them can do is 49 kilos and they have to be on the limit weight to get down to that. That's 0.5 above the weight for age scale (it's 48.5 kgs for November at 2400).

Taking the same situation in February, without claims they still cannot match him, as the older horse is still 2.5 under weight for age, while their weight for age scale puts them at 51.5 (and the limit weight is 52 – there would have to be a claim even if they were on the limit).

So, other things being equal, there is a clue here for the investor. A horse that is as good as the rest is 'in light', as they say, on the tried and time-honoured scale. He may not win but two hundred years of testing say that he has a big show.

There are many other factors, not the least of which is the horse's proven ability (or otherwise) to carry the weight he has been allotted. But there can be no doubting that weight for age figures can assist you to identify well-placed horses in handicaps. The reverse is not true. You do not get a good line on weight for age races by studying handicaps!

Investors have found to their cost over the years that the weight for age race is a thing apart, that there are some horses who perform best under the scale and some who simply cannot make the grade.

So many times we see comments in our guides to the effect that a certain horse in a weight for age event is a 'handicapper'. This horse might have performed well with big weights in handicaps, yet he cannot repeat the effort at what would seem to be advantageous terms. This is where class comes into play. The best horses win weight for age events. Class ... a subject for another day!

The conclusion to this? The conclusion is that an investor must never lose sight of the weight for age scale when comparing horses with reasonably equal chances. While it may seem that one contender has a big edge, a quick study of the relative weights (remember that the limit weight is a vital factor) may tell a very different tale.

By Ian Macarthur