Identifying Guessing in English Language Tests via Rasch Fit Statistics: An Exploratory Study
Bibliographic record
Abstract
This article explores the issue of identifying guessers – with a specific focus on multiple-choice tests. Guessing has long been considered a problem due to the fact that it compromises validity. A test taker scoring higher than they should through guessing does not provide a picture of their actual ability. After an initial description of issues associated with guessing, the article then outlines approaches which have been taken to either discourage test takers from guessing or which attempt statistically to handle the problem. From this, the article moves to a novel way of identifying potential guessers: from the post hoc use of Rasch fit statistics. Two datasets, each consisting of approximately 200 beginner level English language test takers were split into two. In each dataset, half the test takers’ answers were randomised – to approximate guessing. Results obtained via a Rasch analysis of the data was then passed to an analyst who used the Rasch fit statistics to identify possible guessers. On each dataset, 80% of guessers were identified.
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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 | 0.048 | 0.171 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".