Anomalous Differences Between the Global Lung Function Initiative 2023 and 2012 Spirometry Reference Values
Bibliographic record
Abstract
BACKGROUND: In 2012, the Global Lung Function Initiative (GLI) collected a large international database of spirometry measurements in healthy people from which predicted spirometric values were derived based on sex, age, and height for people from 4 different geographic ancestral groups. In 2023, a single set of predicted spirometry values was developed for the entire data set, designed to be independent of ancestry. RESEARCH QUESTION: What impact do differences in the proportion of participants from the 4 ancestral groups at each age cohort of the GLI database have on differences between predicted values using the 2012 and 2023 equations? STUDY DESIGN AND METHODS: Because 77.4% of participants in the GLI spirometry database are of broadly European ancestry, the GLI 2023 spirometry reference values used an inverse probability weighting to approximate an equal contribution of each of the 4 different ancestral groups to develop predicted global spirometric values. This study examined the consequences of using a constant inverse probability weighting factor for each ancestral group over the entire age range from 3.5 to 95 years. RESULTS: The proportional number of participants from each ancestry group in each age cohort varied considerably. The contribution of the European ancestry group, which had the largest predicted lung volumes, was highest in younger children and in older adults. The net effect was that when using GLI 2023 spirometry reference values, predicted lung volumes in older adults were higher than the lung volumes predicted for any of the 4 individual ancestral groups using GLI 2012 spirometry reference values. The opposite effect was found in children and adolescents. INTERPRETATION: It was concluded that the inverse weighting strategy used to develop the GLI 2023 spirometric reference values introduced a systematic bias that skewed the predicted values, producing progressively overestimated predicted lung volumes with increasing age in adults and progressively underestimated predicted lung volumes with increasing age in children and adolescents.
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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 | 0.017 | 0.048 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".