This is a copy of a shared ChatGPT conversation
ChatGPT said:
Under the assumptions we've converged on, the argument becomes fairly clean.
Assumptions
-
Initial rating at the median:
R0=1500. -
Total games:
N=963. -
Win rate:
W=57.32%=0.5732. -
Opponents are matched by current rating.
-
Elo-like rating system.
-
Half the games are solo and half are party, but because each ladder only receives half the games, the effective K for each ladder is taken to be half the nominal value. Thus we use
K=10.
Rating gain
For opponents of equal rating, the expected gain per game is
ΔRgame=K(W−0.5).Substituting,
ΔRgame=10(0.5732−0.5)=10(0.0732)=0.732.Over 963 games,
ΔR=963×0.732=704.916.Therefore,
Rf=1500+704.916=2204.916.So the inferred current rating is
Rf≈2205.Convert to percentile
Assume the rating pool is approximately normal,
R∼N(μ,σ2),with
-
mean (median)
μ=1500, -
standard deviation
σ=300.
The standardized score is
z=3002205−1500=2.35.The cumulative normal distribution gives
Φ(2.35)≈0.9906.Therefore,
Percentile≈99.06%.This corresponds to
100−99.06=0.94%of players being above you.
Comparison with your recollection
You recalled that this was approximately the top 1% in Dota 2.
Our estimate gives
99.06%≈top 0.94%,which is remarkably consistent.
This agreement is meaningful because the estimate did not use your recollection as an input. It followed from:
-
starting near the median,
-
963 games,
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a 57.32% lifetime win rate,
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rating-based matchmaking,
-
an effective K=10.
The recollection therefore acts as an independent validation that these assumptions are in the right ballpark.
One important caveat
The weakest assumption is actually σ=300, not the Elo calculation. If the Dota 2 rating distribution had, say, σ=350, then
z=350705=2.01,which corresponds to about the 97.8th percentile (top 2.2%).
If σ=250,
z=250705=2.82,which corresponds to about the 99.76th percentile (top 0.24%).
So the percentile depends strongly on the actual spread of the rating distribution.
However, historical evidence from Dota 2 suggests that the effective spread of the matchmaking rating distribution was indeed on the order of a few hundred MMR-equivalent points, making a result very close to the top 1% entirely plausible. In other words, your inferred rating gain of about 705 Elo-equivalent points and your recollection of being around the 99th percentile are mutually consistent.