IDPA scoring is based on penalties for points dropped rather than rewards for points scored. If all your shots fall in the 8" center-of-mass circle or the 6" square head (zero points down or -0), then your score is simply the time it took you to shoot the stage. Lowest score wins.
If you have hits outside the central circle and head they are counted for points down (number of points less than perfect). The first area just outside the central circle counts one point down (-1) and the outer area counts three points down (-3). You would add 1/2 (.50) second for each point down.
For instance, say you shot a stage that required at least 2 shots on each of three targets. After firing the stage your time was 12.53 seconds - if all your shots are in the -0 zones, your final score is 12.53.
Now, the same stage and the same time but you have a -1 on the first target and a -1 and a -3 on the third target. That's -1, -1 and -3 for a total of -5 points. Then multiply 5 x the .5 second penalty for each point down and you get 2.5 seconds in penalties that you add to your original time. You actual score would be 15.03 instead of the original time it took.
You can also incur penalties for precedural errors (add 3 seconds), hitting a non-threat target (add 5 seconds) and so on.
The .5 second penalty doesn't sound like much but they add up quickly. In IDPA you will almost always be better off taking the small amount of extra time it takes to get good hits rather than shooting blazingly fast with several points down.
Mikey
