Measurement and effect of income on colorectal cancer survival and the diagnostic interval
Bibliographic record
Abstract
Colorectal cancer (CRC) patients experiencing low income have worse outcomes throughout the cancer continuum.Income inequalities in the diagnostic interval, the time from presentation of symptoms to the healthcare system to cancer diagnosis, may partially explain these outcomes.With increasing interest in income-related differences in cancer outcomes, accurate measurement of income is imperative, and misclassification of income can result in wrong conclusions about the presence of income inequalities.The overarching goal of this thesis was to estimate income inequalities in survival and the diagnostic interval for CRC patients in Canada and to advance knowledge regarding how the measurement of income at the individual and neighbourhood levels impacts those estimated inequalities.The first manuscript determines misclassification between individual-and neighbourhood-level income and their association with survival among CRC patients diagnosed from 1992 to 2017 in the Canadian Census Health and Environment Cohorts.I found very poor agreement between individual and neighbourhood income, with only 17% of respondents assigned to the same quintile (weighted kappa=0.18).Individual income had a greater effect on relative and additive survival than neighbourhood income.The interaction between individual and neighbourhood income demonstrated that those in the lowest individual and neighbourhood income quintiles were the most at risk for poor survival.The poor agreement between these two measures fed directly into the second manuscript, where I used probabilistic bias analyses to adjust for exposure misclassification bias resulting from using neighbourhood income as a proxy for individual income when examining 5-year survival.The bias analysis resulted in similar relative risks (RR) for bias-adjusted neighbourhood income compared to true individual income.For example, the bias-adjusted RR for the lowest income quintile compared to the highest Conclusion.Cancer researchers should avoid using neighbourhood income as a proxy for individual income, especially among patients with cancers with demonstrated inequalities by income.
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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 | 0.003 | 0.034 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".