Introducing: Impact Rating
Adding context to KD by putting an emphasis on winning games
In this article, I outline a new stat that helps to take the Kill-Death Ratio (KD) to the next level by adding some additional context while still keeping the result easy to calculate and understand.
KD is extremely popular; it’s probably the first stat any competitive first-person shooter player learns about. While I think KD is extremely flawed, and have written about it here (and here and here) in the past, it’s easy to see why it’s so loved. KD is easy and accessible. It shows on the scoreboard at the end of every game!
KD doesn’t consider the game’s outcome!
Without considering the outcome, any player can play for KD by making plays that negatively impact their team’s chances to win. Last season, 38 players had positive KDs in HP games that their team lost by 100+ points! How impactful were those kills? As Herm Edwards would say:
The Equation
Three simple equations get us from a player’s KD to Impact Rating:
- Points Per Kill (PPK) = Points Scored / Team Kills
- Points Against Per Death (PAPD) = Opponent Points Scored / Team Deaths
- Impact = (Player Kills x PPK) — (Player Deaths x PAPD)
Think of Impact Rating as weighting the importance of a player’s kills and deaths by how many points the entire team could score or concede per kill or death. Playing against a team that can convert kills into points easily? Well, you better not die as often! The same goes for maps that tend to come with fewer engagements per point scored (think — Terminal HP).
That’s it. This simple change greatly affects how we interpret final scores in games. The change is especially important in HP, but impacts SND and CTL too. Let’s look at some examples.
Who had a better game here, Scrap or Estreal? Estreal finished with a 1.29 KD (+4), while Scrap had a 0.75 KD (-5). Well, the important piece of information we haven’t mentioned: TOR won by 100 points!! TOR scored 250 points on 70 kills, or 3.57 PPK. LAG only mustered a 2.28 PPK. To put it another way, from TOR’s perspective, dying just didn’t matter as much since LAG couldn’t convert. On the other hand, each kill TOR got added a lot of points (1.57x more than LAG!).
Doug Drama
The better, more handsome Doug was making the Twitter rounds this week after this screenshot was posted of a game he won:
Doug’s team had 250 points with 72 kills; the opponent had 201 with 73 kills. Applying our above equations:
- PPK = 250 / 72 = 3.47 points per kill
- PAPD = 201 / 73 = 2.75 points against per death
- Net Points = 4 x 3.47–17 x 2.75 = -32.9 points
- Impact Rating = 0.52
For context, this is a pretty poor Impact in Hardpoint, but not wildly so. In fact, there have been 6 performances in the CDL in HP with worse Impacts already in Week 1 of MW3!
I’ll be tweeting out some scoreboards for games so you can judge for yourself if this new stat is worth your time. But I think Doug puts into words best why we need a new stat…
BECAUSE KILLS ARE GLORIFIED FOR FANS TO THINK BETTER STATS MEANS MORE WINS!
