2-minute case / observed SBA loans

Same review budget.
Different results.

Do better probabilities produce a better review list? Compare raw and independently calibrated scores on the same later loans in a 35,000-loan SBA study. Keep the weaker results visible.

10,000 held-out loans89 recorded charge-offs24-month outcome horizonNo sign-in or installation

01 / keep the workload equal

Give each method the same review slots

Fixed research capacities / Review slots

Current comparison: each method reviews 1,000 / 10,000 loans.

Constant baseline

7 / 89 recorded events

7
Precision
0.70%
Event capture
7.87%

82 events remain outside this review list.

Raw Logistic

26 / 89 recorded events

26
Precision
2.60%
Event capture
29.21%

63 events remain outside this review list.

Independent isotonic

24 / 89 recorded events

24
Precision
2.40%
Event capture
26.97%

65 events remain outside this review list.

Raw Logistic captures 26 events: precision is 26 / 1,000 = 2.60%; event capture is 26 / 89 = 29.21%. The denominators answer different questions.

These are historical event concentrations, not prevented losses. All three capacities were fixed in the research protocol. Switching reads verified results; it does not refit a model or choose a deployment threshold. Constant-score ties use record ID, so that list is an arbitrary ordering.

02 / probability ≠ ranking

Calibration can lower error.
Ranking can still get worse.

The same 10,000 test loans; these metrics do not change with capacity
Fixed methodAUC ↑Brier ↓
Constant baseline0.50000.009838
Raw Logistic0.67230.009011
Independent isotonic0.65840.008819

Brier measures squared probability error; AUC measures ordering between positive and negative records. Isotonic calibration can introduce tied scores, so probability error, ranking and fixed-budget capture need separate checks. There are only 89 test events: a single difference is no future guarantee. The full report retains paired funding-month bootstrap intervals.

03 / dates before models

Let outcomes mature
before the next stage.

  1. Train: 20,000 loans funded in 2006–2010. Fit preprocessing and Logistic only on training loans. The latest 24-month horizon ends in 2012.
  2. Calibrate separately: 5,000 loans funded in 2013. Only these labels fit isotonic calibration. Their latest horizon ends in 2015.
  3. Test: 10,000 loans funded in 2016–2017. Evaluate fixed models and capacities. Test outcomes do not tune features or hyperparameters.

The final public snapshot has actual funding dates but no historical first-publication times or feature revisions. This is retrospective funding-cohort validation. It cannot certify which features were available at past decisions or directly represent current Chinese retail credit.

See all 9 fixed-capacity comparisons
MethodCapacityReviewedCaptured / all eventsPrecisionEvent capture
Constant baseline5%5004 / 890.80%4.49%
Constant baseline10%1,0007 / 890.70%7.87%
Constant baseline20%2,00016 / 890.80%17.98%
Raw Logistic5%50014 / 892.80%15.73%
Raw Logistic10%1,00026 / 892.60%29.21%
Raw Logistic20%2,00038 / 891.90%42.70%
Independent isotonic5%50017 / 893.40%19.10%
Independent isotonic10%1,00024 / 892.40%26.97%
Independent isotonic20%2,00037 / 891.85%41.57%

Scroll the table horizontally on a small screen. Buttons and table share the same refitted, verified evidence. No new training or selection occurs here.

04 / follow a number back to its source

Follow one number through the project.

Fixed-capacity CSV → 10,000 test predictions → Training and verification code → Frozen protocol. This page contains aggregates only. Inspect the brief data and source digests.

Use Python 3.12+ in a virtual environment. Installation needs internet; the published v0.8.1 study then refits offline. The current website build generates this reader brief.

python -m pip install https://github.com/dev-belly/CreditVintage/releases/download/v0.8.1/creditvintage_research-0.8.1-py3-none-any.whl
python -m creditvintage sba-benchmark --out outputs/sba-credit
python -m creditvintage verify-sba outputs/sba-credit

Choose a new output directory. Successful verification reports status: verified and refitted: true: internal consistency under this implementation, not independent adoption or business benefit.