Bibliographic record
Abstract
Tree-based methods, or decision tree methods, may be used for two broad types of problem–classification and regression. These methods may be appropriate when there are extensive data, and there is uncertainty about the form in which explanatory variables ought to enter into the model. They may be useful for initial data exploration. Tree-based methods have been especially popular in the data mining community. Tree-structured classification has a long history in biology, where informal methods of dendrogram construction have been in use for centuries. Social scientists began automating tree-based procedures for classification in the 1940s and 1950s, using methods which are similar to some of the current partitioning methods; see Belson (1959). Venables and Ripley (2002, Chapter 9) give a short survey of the more recent history. The tree-based regression and classification methodology is radically different from the methods discussed thus far in this book. The theory that underlies the methods of earlier chapters has limited relevance to tree-based methods. The methodology is relatively easy to use and can be applied to a wide class of problems. It is at the same time insensitive to the nuances of particular problems to which it may be applied. The methodology makes limited use of the ordering of values of continuous or ordinal explanatory variables. In small data sets, it is unlikely to reveal data structure. Its strength is that, in large data sets, it has the potential to reflect relatively complex forms of structure, of a kind that may be hard to detect with conventional regression modeling.
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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 | 0.005 | 0.017 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.004 | 0.008 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.005 | 0.006 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.020 | 0.017 |
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".