ACR

What is it?

Like in the IATF's Collins Rating System (CRS), a thrower's Axe Charts Rating (ACR) is a way of summarizing their skill level in a single number. In both systems, a thrower is expected to win a match if their opponent has a lower rating.

Why was it made?

Axe throwing is an accuracy sport. While we do compete head-to-head, there's nothing you can do to force your opponent to lose. At the end of the match, the more consistently accurate thrower will outscore their opponent in enough rounds and win. If your rating is meant to indicate whether you're expected to beat another thrower, then it should be based on the accuracy of your previous throws and not on whether you've won or lost against your previous opponents - as previous outcomes do not determine future success.

How does it differ from CRS?

Your Collins rating is based on the actual outcome (win, loss, or tie) of each round compared to the expected round outcomes, while your Axe Charts rating is based on how accurately you throw. Let's look at a match between two hypothetical throwers: Alice and Bob. Alice is more accurate than Bob and has a higher rating in both systems. In the match, Alice throws three 25 point rounds and Bob throws a 21, 25, and 19.

Since Alice has a higher CRS rating than Bob, she is expected to beat Bob in each round. Because Alice tied a round with Bob when she was expected to win it, she'll lose CRS points even though she threw accurately and won the match. Bob upset the expectation in a single round and gained points at Alice's expense.

In that same match, Alice would not lose ACR points just because Bob had a strong round. Instead, each thrower would gain or lose ACR points independently based on how accurate they were. Bob cannot do anything in the match to affect Alice's rating. Both throwers' ratings are a reflection of their own skill level and a better indicator of their future success.

How does it work?

Your Axe Charts Rating is a reflection of your accuracy on both targets (bullseye and clutch) in both disciplines (hatchet and Big Axe). Since you get more points for more accurate throws, the number of points earned is a good measure of accuracy. Your rating value is a ratio of the total points earned to the total points available. As an example, an 852 ACR value means that the thrower has earned 85.2% of all available points and is therefore regarded has having 85.2% accuracy across all disciplines and targets. The basic idea is expressed in the simplified formula below:

ACR = Points Earned / Points Available

This division produces a decimal number between 0 and 1. Multiplying this decimal number by 1000 makes it a 3 digit number (or 4 if your accuracy is perfect). The final rating value is that 3 digit number rounded to the nearest integer. These details are reflected in the formula below:

ACR = Round(1000 * Points Earned / Points Available)

When clutch is called, technically the number of points available for that throw should be 7. However, adding 7 to the denominator of the formula would penalize throwers more for a missed clutch than for a dropped axe. Instead, the formula treats every throw as if there are only 5 points available. This way, a missed clutch incurs the same penalty as a dropped axe but a hit clutch awards an outsized benefit: gaining 7/5 available points instead of the 5/5 available points for a bullseye. The final form of the formula is shown below:

ACR = Round((1000 * Points Earned) / (5 * Total Throws))