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)
86.2%
Mean accuracy (100−APE)
84.0%
Within ±5%
13%
Within ±10%
34%
Within ±20%
75%
Bias
-3.9%
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 | 182 | 86.6% | 35% | -3.8% |
| middle | 3 | 82.5% | 0% | +23.2% |
| grail | 7 | 77.4% | 29% | -18.0% |
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 |
|---|---|---|---|---|---|---|
| #1194 | floor · high | Sep 14, 2026 | 0.489Ξ | 0.454Ξ | -7.1% | 92.9% |
| #1194 | floor · high | Sep 14, 2026 | 0.440Ξ | 0.474Ξ | +7.7% | 92.3% |
| #673 | floor · high | Sep 14, 2026 | 0.475Ξ | 0.455Ξ | -4.2% | 95.8% |
| #51 | floor · high | Sep 13, 2026 | 0.600Ξ | 0.444Ξ | -26.0% | 74.0% |
| #3835 | floor · high | Sep 13, 2026 | 0.406Ξ | 0.468Ξ | +15.3% | 84.7% |
| #2310 | floor · high | Sep 12, 2026 | 0.433Ξ | 0.550Ξ | +27.0% | 73.0% |
| #4017 | floor · high | Sep 12, 2026 | 0.431Ξ | 0.455Ξ | +5.6% | 94.4% |
| #3795 | floor · high | Sep 12, 2026 | 0.446Ξ | 0.428Ξ | -4.0% | 96.0% |
| #673 | floor · high | Sep 12, 2026 | 0.442Ξ | 0.482Ξ | +9.1% | 91.0% |
| #3509 | floor · high | Sep 12, 2026 | 0.799Ξ | 0.479Ξ | -40.1% | 60.0% |
| #3518 | floor · high | Sep 12, 2026 | 0.630Ξ | 0.478Ξ | -24.1% | 75.9% |
| #3509 | floor · high | Sep 12, 2026 | 0.463Ξ | 0.502Ξ | +8.4% | 91.6% |
| #3518 | floor · high | Sep 12, 2026 | 0.452Ξ | 0.548Ξ | +21.2% | 78.8% |
| #3820 | floor · high | Sep 11, 2026 | 0.462Ξ | 0.494Ξ | +6.9% | 93.1% |
| #58 | floor · high | Sep 11, 2026 | 0.461Ξ | 0.445Ξ | -3.5% | 96.5% |
| #3512 | floor · high | Sep 11, 2026 | 0.574Ξ | 0.453Ξ | -21.1% | 78.9% |
| #2874 | floor · high | Sep 11, 2026 | 0.464Ξ | 0.524Ξ | +12.9% | 87.1% |
| #242 | floor · high | Sep 11, 2026 | 0.464Ξ | 0.428Ξ | -7.8% | 92.2% |
| #4405 | floor · high | Sep 11, 2026 | 0.550Ξ | 0.448Ξ | -18.6% | 81.5% |
| #2998 | floor · high | Sep 11, 2026 | 0.499Ξ | 0.425Ξ | -14.8% | 85.2% |
| #4364 | floor · high | Sep 11, 2026 | 0.493Ξ | 0.437Ξ | -11.4% | 88.6% |
| #3507 | floor · high | Sep 11, 2026 | 0.493Ξ | 0.428Ξ | -13.2% | 86.8% |
| #2028 | floor · high | Sep 11, 2026 | 0.495Ξ | 0.460Ξ | -7.1% | 92.9% |
| #4359 | floor · high | Sep 11, 2026 | 0.493Ξ | 0.409Ξ | -17.0% | 83.0% |
| #5438 | floor · high | Sep 11, 2026 | 0.520Ξ | 0.462Ξ | -11.2% | 88.9% |
| #4392 | floor · high | Sep 11, 2026 | 0.494Ξ | 0.409Ξ | -17.2% | 82.8% |
| #3930 | floor · high | Sep 11, 2026 | 0.875Ξ | 0.421Ξ | -51.9% | 48.1% |
| #2153 | middle · high | Sep 11, 2026 | 0.600Ξ | 0.705Ξ | +17.5% | 82.5% |
| #2966 | middle · high | Sep 11, 2026 | 0.600Ξ | 0.692Ξ | +15.3% | 84.7% |
| #4344 | floor · high | Sep 10, 2026 | 0.467Ξ | 0.396Ξ | -15.2% | 84.8% |
| #1276 | floor · high | Sep 10, 2026 | 0.425Ξ | 0.401Ξ | -5.7% | 94.4% |
| #3777 | floor · high | Sep 10, 2026 | 0.435Ξ | 0.423Ξ | -2.8% | 97.2% |
| #3770 | floor · high | Sep 10, 2026 | 0.450Ξ | 0.440Ξ | -2.2% | 97.8% |
| #2573 | floor · high | Sep 10, 2026 | 0.470Ξ | 0.428Ξ | -8.9% | 91.1% |
| #1982 | floor · high | Sep 9, 2026 | 0.620Ξ | 0.443Ξ | -28.6% | 71.5% |
| #2573 | floor · high | Sep 9, 2026 | 0.409Ξ | 0.423Ξ | +3.4% | 96.6% |
| #5188 | floor · high | Sep 9, 2026 | 0.484Ξ | 0.408Ξ | -15.7% | 84.3% |
| #947 | floor · high | Sep 8, 2026 | 0.490Ξ | 0.451Ξ | -8.0% | 92.0% |
| #4411 | floor · high | Sep 8, 2026 | 0.593Ξ | 0.486Ξ | -18.0% | 82.0% |
| #5340 | middle · high | Sep 8, 2026 | 0.475Ξ | 0.649Ξ | +36.6% | 63.4% |
Model chimpers-1789415303-2026-08-03.2 · evaluated through 9/14/2026. Method details on the methodology page.