Accuracy
How accurate is the Chimpers model?
Every score comes from the newest chronological hold-out; the target sale is excluded from training, comparables, and its causal floor proxy.
Median accuracy (100−APE)
91.2%
Mean accuracy (100−APE)
89.4%
Within ±5%
27%
Within ±10%
59%
Within ±20%
89%
Bias
-2.0%
Accuracy by market tier
Floor, middle-market, and grail sales are scored separately so aggregate accuracy cannot hide a weak segment
| Tier | Sales | Median accuracy | Within ±10% | Bias |
|---|---|---|---|---|
| floor | 145 | 91.3% | 61% | -1.6% |
| middle | 2 | 68.0% | 0% | -32.1% |
| grail | 2 | 68.1% | 0% | -4.8% |
Weekly median accuracy
Chronological hold-out accuracy by sale week
Error distribution
Signed hold-out error; positive means over-predicted
Scored hold-out sales
60 out-of-sample predictions frozen at evaluation time
| Item | Tier / evidence | Date | Sale | Model | Error | Accuracy |
|---|---|---|---|---|---|---|
| #3615 | floor · high | Aug 4, 2026 | 0.681Ξ | 0.696Ξ | +2.2% | 97.8% |
| #4647 | floor · high | Aug 3, 2026 | 0.650Ξ | 0.609Ξ | -6.3% | 93.7% |
| #806 | floor · high | Aug 3, 2026 | 0.634Ξ | 0.601Ξ | -5.2% | 94.8% |
| #3890 | floor · high | Aug 3, 2026 | 0.634Ξ | 0.603Ξ | -4.9% | 95.1% |
| #4647 | floor · high | Aug 3, 2026 | 0.531Ξ | 0.671Ξ | +26.4% | 73.6% |
| #3890 | floor · high | Aug 3, 2026 | 0.590Ξ | 0.653Ξ | +10.7% | 89.3% |
| #806 | floor · high | Aug 2, 2026 | 0.591Ξ | 0.675Ξ | +14.2% | 85.8% |
| #4621 | middle · high | Aug 2, 2026 | 2.990Ξ | 1.407Ξ | -52.9% | 47.1% |
| #4621 | floor · medium | Aug 2, 2026 | 1.410Ξ | 0.728Ξ | -48.4% | 51.6% |
| #1647 | floor · high | Aug 1, 2026 | 0.650Ξ | 0.678Ξ | +4.3% | 95.7% |
| #1027 | floor · high | Aug 1, 2026 | 0.620Ξ | 0.692Ξ | +11.6% | 88.4% |
| #752 | floor · high | Jul 31, 2026 | 0.660Ξ | 0.757Ξ | +14.7% | 85.3% |
| #3500 | floor · high | Jul 30, 2026 | 0.743Ξ | 0.668Ξ | -10.1% | 89.9% |
| #3619 | floor · high | Jul 30, 2026 | 0.630Ξ | 0.821Ξ | +30.3% | 69.7% |
| #2244 | floor · high | Jul 29, 2026 | 0.788Ξ | 0.665Ξ | -15.6% | 84.4% |
| #5445 | floor · high | Jul 29, 2026 | 0.640Ξ | 0.700Ξ | +9.4% | 90.6% |
| #392 | floor · high | Jul 28, 2026 | 0.856Ξ | 0.732Ξ | -14.5% | 85.6% |
| #3767 | floor · high | Jul 28, 2026 | 0.710Ξ | 0.663Ξ | -6.6% | 93.4% |
| #5181 | floor · high | Jul 28, 2026 | 0.719Ξ | 0.680Ξ | -5.4% | 94.6% |
| #3767 | floor · high | Jul 28, 2026 | 0.630Ξ | 0.711Ξ | +12.9% | 87.1% |
| #4844 | floor · high | Jul 28, 2026 | 0.640Ξ | 0.699Ξ | +9.2% | 90.8% |
| #5090 | floor · high | Jul 28, 2026 | 0.721Ξ | 0.700Ξ | -2.9% | 97.1% |
| #170 | floor · high | Jul 28, 2026 | 0.800Ξ | 0.691Ξ | -13.6% | 86.4% |
| #540 | floor · high | Jul 27, 2026 | 0.790Ξ | 0.704Ξ | -10.9% | 89.1% |
| #3187 | floor · high | Jul 27, 2026 | 0.650Ξ | 0.653Ξ | +0.5% | 99.5% |
| #3272 | floor · high | Jul 26, 2026 | 0.750Ξ | 0.723Ξ | -3.6% | 96.4% |
| #1110 | floor · high | Jul 26, 2026 | 0.808Ξ | 0.675Ξ | -16.4% | 83.6% |
| #896 | floor · high | Jul 26, 2026 | 0.710Ξ | 0.644Ξ | -9.3% | 90.7% |
| #1294 | floor · high | Jul 26, 2026 | 0.680Ξ | 0.620Ξ | -8.8% | 91.2% |
| #3626 | floor · high | Jul 26, 2026 | 0.675Ξ | 0.742Ξ | +9.9% | 90.1% |
| #857 | floor · high | Jul 26, 2026 | 0.696Ξ | 0.635Ξ | -8.8% | 91.2% |
| #3815 | floor · high | Jul 26, 2026 | 0.704Ξ | 0.649Ξ | -7.8% | 92.2% |
| #1013 | floor · high | Jul 26, 2026 | 0.701Ξ | 0.613Ξ | -12.6% | 87.5% |
| #1364 | floor · high | Jul 26, 2026 | 0.699Ξ | 0.643Ξ | -8.0% | 92.0% |
| #3846 | floor · high | Jul 26, 2026 | 0.675Ξ | 0.638Ξ | -5.5% | 94.5% |
| #3716 | floor · high | Jul 26, 2026 | 0.675Ξ | 0.676Ξ | +0.2% | 99.9% |
| #215 | floor · high | Jul 26, 2026 | 0.709Ξ | 0.699Ξ | -1.4% | 98.7% |
| #5049 | floor · high | Jul 26, 2026 | 0.675Ξ | 0.726Ξ | +7.6% | 92.4% |
| #896 | floor · high | Jul 26, 2026 | 0.615Ξ | 0.656Ξ | +6.7% | 93.3% |
| #896 | floor · high | Jul 25, 2026 | 0.650Ξ | 0.611Ξ | -6.0% | 94.0% |
Model chimpers-1785802391-2026-08-03.2 · evaluated through 8/4/2026. Method details on the methodology page.