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How accurate are RennPulse valuations?

Our XGBoost model is validated against a 20% holdout set every week. Here are the latest numbers — unfiltered, by market segment.

86.8%R² (variance explained)
24.0%MAPE (avg prediction error)
3,933Auction sales in model
22Predictive features

v2.1 improvement: R² up from 71.7% to 86.8% (+15.1pts) · MAPE down from 25.7% to 24.0% (-1.7pts) · 216 statistical outliers filtered via MAD

How we measure accuracy

22-Feature XGBoost Model

Gradient-boosted regression trained on log-transformed prices across 22 engineered features — generation, trim, year, mileage, car age, transmission, color tier, geography, premium options, platform dynamics, seasonality, and interaction terms.

Weekly Retrained, Holdout Validated

Model retrains weekly on 2,973 samples with a 744-sample holdout set stratified by market segment. Recency-weighted (6-month half-life) with MAD-based outlier filtering and Bayesian prior blending for thin segments.

MAPE Scoring

Mean Absolute Percentage Error measures average prediction distance. Lower is better. Under 15% = high confidence. Under 25% = good. Above 25% = fair.

Accuracy by market segment

Sample of holdout validation results (744 sales withheld from training). Model v2.1.

911 (All Generations)Fair

Carrera, Targa, Turbo, GTS, Speedster — 930 through 992

R²

82.6%

MAPE

25.7%

Holdout n

525

R² fit
82.6%
GT & Special EditionsGood

GT3, GT3 RS, GT2, GT2 RS, GT4, GT4 RS, R, S/T, Sport Classic

R²

70.8%

MAPE

19.9%

Holdout n

40

R² fit
70.8%
Cayman & BoxsterGood

986, 987, 981, 718 — all trims including GT4 & Spyder

R²

91%

MAPE

20%

Holdout n

179

R² fit
91%

Prediction examples

Real holdout predictions where the model nailed the sale price.

2018 911 GT3 (991.2)

Manual, 8k miles, Guards Red

Predicted

$178,500

Sold For

$181,000

Error

1.4%

2015 Cayman GTS (981c)

PDK, 32k miles, Sapphire Blue

Predicted

$54,200

Sold For

$52,750

Error

2.7%

2020 911 Carrera S (992)

PDK, 14k miles, GT Silver

Predicted

$109,800

Sold For

$112,000

Error

2.0%

Top predictive features

What drives the price prediction most, ranked by XGBoost feature importance.

Generation
30.2%
Model Year
22.6%
Car Age at Sale
16%
Trim Level
8.7%
Mileage
2.5%

Last retrained May 11, 2026. Metrics refresh automatically with each weekly retrain.

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