Minimizing misclassification bias with a model to identify acetabular fractures using health administrative data
Bibliographic record
Abstract
ABSTRACT: Acetabular fractures (AFs) are relatively uncommon thereby limiting their study. Analyses using population-based health administrative data can return erroneous results if case identification is inaccurate ('misclassification bias'). This study measured the impact of an AF prediction model based exclusively on administrative data upon misclassification bias.We applied text analytical methods to all radiology reports over 11 years at a large, tertiary care teaching hospital to identify all AFs. Using clinically-based variable selection techniques, a logistic regression model was created.We identified 728 AFs in 438,098 hospitalizations (15.1 cases/10,000 admissions). The International Classification of Disease, 10th revision (ICD-10) code for AF (S32.4) missed almost half of cases and misclassified more than a quarter (sensitivity 51.2%, positive predictive value 73.0%). The AF model was very accurate (optimism adjusted R2 0.618, c-statistic 0.988, calibration slope 1.06). When model-based expected probabilities were used to determine AF status using bootstrap imputation methods, misclassification bias for AF prevalence and its association with other variables was much lower than with International Classification of Disease, 10th revision S32.4 (median [range] relative difference 1.0% [0%-9.0%] vs 18.0% [5.4%-75.0%]).Lone administrative database diagnostic codes are inadequate to create AF cohorts. The probability of AF can be accurately determined using health administrative data. This probability can be used in bootstrap imputation methods to importantly reduce misclassification bias.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.095 | 0.185 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.004 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".