There is a lot of jargon when it comes to the world of archery and it will inevitably be confusing if you're new to the sport. Some of these terms are risers, limbs, tillers and cams which refer to actual parts of the bow, but others, such as IBO, draw length and draw weight refer to performance features of the bow. Let-off is one of those features that you'll find important.

The design of the compound bow has been done so that the draw weight decreases at the end of the drawstroke giving the shooter more time to aim and release the arrow. To explain further, as you draw back the bowstring the weight increases steadily until you reach a certain point at which time the cam system takes over and it becomes much lighter so that by the end of the draw the shooter is only holding a fraction of the weight they were at the start of the draw.

In the past when you drew a bow, especially if you owned a longbow or a recurve bow you would have noticed that it takes a lot of strength to draw the bowstring back and then hold it while aiming for any length of time. Traditional bows have the most draw weight at the end of the draw which means it is particularly tiring if you try to hold the bow drawn for any length of time.

Early compound bows gave you a let-off of 35-50% but nowadays the norm is more in the region of 75-80%, with some bows featuring an adjustable let-off. So a bow with a 70 lb draw weight and 80% let-off will converts to a draw weight of only 14 lbs.

It's not always a good thing to have use a bow with super-high let-off at full draw because it allows the arrow to move more easily in the shooting position. You need some resistance to maintain a good natural alignment.

The let-off is listed by bow manufacturers as a percentage in their literature, sometimes you might see two numbers advertised next to the Let-off statistic. They will be "Effective" and "Actual" let-off. It might help to explain the difference between effective and actual let-off.

Quite often when a compound bow's specifications are listed by a bow manufacturer you will see two figures next to the Let-Off heading. You might see the following, Let-Off: 70% Effective, 65% Actual. What this is referring to is the difference in draw weight change between drawing the bow as well as the change in weight when letting the bowstring back down.

To calculate let-off you need to know two things: the minimum weight during draw and the maximum draw weight. These numbers differ depending on whether you are drawing the bow or letting the bow back down. As complicated as the second figure sounds, it's the actual let-off or the let-off experienced when drawing the bow that you will be most concerned with. The figure you're most likely going to see, though is the effective let-off.

A potentially crucial time to remember the impact of effective let-off is after drawing the bow while letting it back down without an arrow fitted. Accidental dry-firing can occur as a result of the high effective let-off and the surprise with which it catches people unprepared. The sudden change in weight can rip the string out of unsuspecting fingers and you could be left with a shattered compound bow.

A final word on let-off is for the trophy hunters out there who want their trophy listed in the Pope and Young Club's record books. Only trophys taken with a bow that had a let-off lower than 65% were included until recently. This has since been changed in 2004 so that those taken with a higher let-off will be listed but an asterisk will be placed by the hunter's name.

So now, when you go out to buy a compound bow and you see the let-off figure you will understand the significance of the numbers. In a nutshell the higher the number, the easier the draw. Now you just have to decide whether that will help or hinder your shooting accuracy.