Severity stratification changes what hallucination rates mean: An item-matched audit of five large language models in orthodontic decision support
| dc.authorid | 0009-0005-3767-7415 | |
| dc.authorid | 0009-0008-8331-9493 | |
| dc.contributor.author | Allaf, Ferdi | |
| dc.contributor.author | Özcan, Mustafa | |
| dc.date.accessioned | 2026-11-13T13:51:35Z | |
| dc.date.available | 2026-11-13T13:51:35Z | |
| dc.date.issued | 2026 | |
| dc.department | Fakülteler, Diş Hekimliği Fakültesi, Klinik Bilimler Bölümü, Ortodonti Ana Bilim Dalı | |
| dc.description.abstract | Background/Objectives: Large language models (LLMs) are consulted for clinical decision support, and their reliability is judged by hallucination prevalence—a measure treating every unsupported element as equivalent, although a fabricated citation and a fabricated protocol differ in what a clinician acting on them would do. We tested whether prevalence tracks clinical risk. Methods: Five LLMs answered a 100-item orthodontic benchmark validated by three external orthodontists (content validity index 0.923). The reference standard was fixed by construction for the 45 items naming a non-existent entity, so any substantive elaboration is unsupported by design; citations were adjudicated against PubMed and CrossRef. Responses were coded with a seven-category taxonomy and assigned to clinical, operational, or epistemic severity tiers in a post hoc exploratory stratification, pre-specified rather than prospectively registered. Because all models answered the same items, comparisons used Cochran’s Q with pairwise McNemar tests and generalised estimating equations clustered on item. Results: Of 500 responses, 449 (89.8%) contained a hallucination but only 65 (13.0%; 95% CI 10.3–16.2) were clinically consequential: prevalence was roughly sevenfold greater than the rate of clinically consequential output as the authors defined it. Between-model differences were large for undifferentiated prevalence (73–100%; Q = 50.51, p < 0.001) and contracted at the clinical tier (10–16%; Q = 10.00, p = 0.040), where no pairwise contrast survived adjustment. Item-level clustering was far stronger for clinically consequential output than for undifferentiated prevalence (intra-class correlation 0.83 versus 0.07). Conclusions: Prevalence and clinically consequential error are not interchangeable and rank models differently. The stratification is exploratory and author-defined, and the benchmark stress-tests susceptibility to fabricated premises rather than surveying natural use. | |
| dc.identifier.citation | Özcan, M., & Allaf, F. (2026). Severity stratification changes what hallucination rates mean: An item-matched audit of five large language models in orthodontic decision support. Diagnostics, 16(19), pp. 1-20. https://doi.org/10.3390/diagnostics16193180 | |
| dc.identifier.doi | 10.3390/diagnostics16193180 | |
| dc.identifier.endpage | 20 | |
| dc.identifier.issn | 2075-4418 | |
| dc.identifier.issue | 19 | |
| dc.identifier.pmid | PMID: 42882334 | |
| dc.identifier.scopusquality | Q1 | |
| dc.identifier.startpage | 1 | |
| dc.identifier.uri | https://doi.org/10.3390/diagnostics16193180 | |
| dc.identifier.uri | https://hdl.handle.net/20.500.13055/1722 | |
| dc.identifier.volume | 16 | |
| dc.identifier.wos | WOS:001904093600001 | |
| dc.identifier.wosquality | Q1 | |
| dc.indekslendigikaynak | Web of Science | |
| dc.indekslendigikaynak | Scopus | |
| dc.indekslendigikaynak | PubMed | |
| dc.indekslendigikaynak.other | SCI-E - Science Citation Index Expanded | |
| dc.institutionauthor | Allaf, Ferdi | |
| dc.institutionauthor | Özcan, Mustafa | |
| dc.institutionauthorid | 0009-0005-3767-7415 | |
| dc.institutionauthorid | 0009-0008-8331-9493 | |
| dc.language.iso | en | |
| dc.publisher | MDPI Publishing | |
| dc.relation.ispartof | Diagnostics | |
| dc.relation.publicationcategory | Makale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.subject | Artificial Intelligence | |
| dc.subject | Large Language Models | |
| dc.subject | Orthodontics | |
| dc.subject | Patient Safety | |
| dc.subject | Clinical Decision Support | |
| dc.subject | Health Information Quality | |
| dc.title | Severity stratification changes what hallucination rates mean: An item-matched audit of five large language models in orthodontic decision support | |
| dc.type | Article | |
| dspace.entity.type | Publication |












