Agreement between Original and Rasch-Approved Neck Disability Index
Bibliographic record
Abstract
Abstract Background: Given the high prevalence of neck pain, the neck disability index (NDI) has been used widely to evaluate patient status and treatment outcomes. Modified versions have been proposed as solutions to measurement deficits in the NDI. However, the original 10-item NDI scored out of 50 is still the commonly administered. Examining the extent of agreement between traditional and Rasch-based versions using Bland-Altman (B&A) plots will inform our understanding of score differences that might rise from using different versions. Therefore, the objective of current study was to describe the extent of agreement between different versions of NDI. Methods: The current study was a secondary data analysis where the study data was compiled from two prospectively collected data source. We performed a comprehensive literature search to identify Rasch-approved NDI within four databases including Embase, Medline, PubMed, and Google Scholar. Modified version to identify Rasch analyses which provided alternative forms and scoring. We graphed B&A plots and calculated the mean difference and the 95% limits of agreement (LoA; ±1.96 times the standard deviation). Results: Two Rasch approved alternative versions (8- and 5- item) were identified from 303 screened publications. We analyzed data from 201 (43 males and 158 females) patients attending community clinics for neck pain. We found that the mean difference was approximately 10% of the total score between the 10-item and 5-item (-4.6 points), whereas the 10-item versus 8-item and 8-item versus 5-item had smaller mean differences (-2.3 points). The B&A plots displayed wider 95% LoA for the agreement between 10-item and 8-item (LoA: -12.0, 7.4) and 5-item (LoA: -14.9, 5.8) compared with the LoA for the 8-item and 5-item (LoA: -7.8, 3.3). Conclusion: Two Rasch-based NDI solutions (8 vs 5 items) that differ in number of items and conceptual construction are available to provide interval level scoring. They both scores that are substantially different from the traditional ordinal NDI, which does not provide interval level scoring. Smaller differences between the two Rasch solutions exist and may relate to the items included. Due to the size and unpredictable nature of the bias between measures, they should not be used interchangeably.
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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 | 0.063 | 0.183 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.010 | 0.007 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".