Development of criteria for the classification and reporting of osteoarthritis: Classification of osteoarthritis of the knee
Abstract
For the purposes of classification, it should be specified whether osteoarthritis (OA) of the knee is of unknown origin (idiopathic, primary) or is related to a known medical condition or event (secondary). Clinical criteria for the classification of idiopathic OA of the knee were developed through a multicenter study group. Comparison diagnoses included rheumatoid arthritis and other painful conditions of the knee, exclusive of referred or paraarticular pain. Variables from the medical history, physical examination, laboratory tests, and radiographs were used to develop sets of criteria that serve different investigative purposes. In contrast to prior criteria, these proposed criteria utilize classification trees, or algorithms.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In a community-based study by Marra et al, 191 of 195 (98.0%) urban-dwelling participants who met the early osteoarthritis criteria also met the American College of Rheumatology clinical criteria for knee osteoarthritis.
“In a community-based study by Marra et al [27], 191 of 195 (98.0%) urban-dwelling participants who met these criteria also met the American College of Rheumatology clinical criteria for knee OA [28].”
From A Community-Based Physical Activity Counselling Program for People With Knee Osteoarthritis: Feasibility and Preliminary Efficacy of the Track-OA Study (2017) · cites this paper as [28]
Cites
Classification and Regression Trees.
Ryzin, J. V., Breiman, L., Friedman, J. H., Olshen, R. A., & Stone, C. J. (1986) · Journal of the American Statistical Association · doi:10.2307/2288003 · Cited by 21,028 · see citing works
The 1982 revised criteria for the classification of systemic lupus erythematosus
Tan, E. M., Cohen, A. S., Fries, J. F., Masi, A. T., Mcshane, D. J., Rothfield, N. F., Schaller, J. G., Talal, N., & Winchester, R. J. (1982) · Arthritis & Rheumatism · doi:10.1002/art.1780251101 · Cited by 14,519 · see citing works
Self-citationRadiological Assessment of Osteo-Arthrosis
Kellgren, J., & Lawrence, J. S. (1957) · Annals of the Rheumatic Diseases · doi:10.1136/ard.16.4.494 · Cited by 12,472 · see citing works
Classification and regression trees
Praagman, J. (1985) · European Journal of Operational Research · doi:10.1016/0377-2217(85)90321-2 · Cited by 10,053 · see citing works
BMDP Statistical Software 1981.
Bubolz, T. A., & Dixon, W. J. (1984) · Journal of the American Statistical Association · doi:10.2307/2288308 · Cited by 5,246 · see citing works
Preliminary criteria for the classification of systemic sclerosis (scleroderma)
Masi, A. T. (1980) · Arthritis & Rheumatism · doi:10.1002/art.1780230510 · Cited by 4,925 · see citing works
Classification and Regression Trees
Jones, E., Harden, S., & Crawley, M. J. (2022) · doi:10.1002/9781119634461.ch20 · Cited by 505 · see citing works
Generalized Osteoarthritis and Heberden's Nodes
Kellgren, J., & Moore, R. (1952) · BMJ · doi:10.1136/bmj.1.4751.181 · Cited by 449 · see citing works
Willkens, R. F., Arnett, F. C., Bitter, T., et al. (1981) · Arthritis & Rheumatism · doi:10.1002/art.1780240612 · Cited by 283 · see citing works
Medical Assessment by a Delphi Group Opinion Technic
Milholland, A. V., Wheeler, S. G., & Heieck, J. J. (1973) · New England Journal of Medicine · doi:10.1056/nejm197306142882405 · Cited by 218 · see citing works
Classification of degenerative arthritis.
Mitchell, N. S., & Cruess, R. (1977) · PubMed · Cited by 36 · see citing works
Altman, R. D., Meenan, R. F., & Hochberg, M. C. (1983) · PubMed · Cited by 28 · see citing works
Self-citation
Flagged first, then by citations
Cited by
Sorted by citations
Epidemiology and burden of osteoarthritis
Litwic, A., Edwards, M. H., Dennison, E. M., & Cooper, C. (2013) · British Medical Bulletin · doi:10.1093/bmb/lds038 · Cited by 1,315 · see citing works
Ziolkowska, M., Koc, A., Luszczykiewicz, G., Ksiezopolska-Pietrzak, K., Klimczak, E., Chwalinska-Sadowska, H., & Maslinski, W. (2000) · The Journal of Immunology · doi:10.4049/jimmunol.164.5.2832 · Cited by 580 · see citing works
McDermott, M. M., Greenland, P., Liu, K., Guralnik, J. M., Celic, L., Criqui, M. H., Chan, C., Martin, G. J., Schneider, J., Pearce, W. H., et al. (2002) · Annals of Internal Medicine · doi:10.7326/0003-4819-136-12-200206180-00008 · Cited by 532 · see citing works
Garnero, P., Piperno, M., Gineyts, E., Christgau, S., Delmas, P. D., & Vignon, E. (2001) · Annals of the Rheumatic Diseases · doi:10.1136/ard.60.6.619 · Cited by 475 · see citing works
Watson, J. A., Ryan, C. G., Cooper, L., Ellington, D., Whittle, R., Lavender, M., Dixon, J., Atkinson, G., Cooper, K., & Martin, D. J. (2019) · The Journal of Pain · doi:10.1016/j.jpain.2019.02.011 · Cited by 428 · see citing works
Factors associated with functional impairment in symptomatic knee osteoarthritis
Creamer, P., Lethbridge‐Cejku, M., & Hochberg, M. C. (2000) · Rheumatology · doi:10.1093/rheumatology/39.5.490 · Cited by 435 · see citing works
Self-citationOnce-Weekly Semaglutide in Persons with Obesity and Knee Osteoarthritis
Bliddal, H., Bays, H., Czernichow, S., Uddén Hemmingsson, J., Hjelmesæth, J., Hoffmann Morville, T., Koroleva, A., Skov Neergaard, J., Vélez Sánchez, P., Wharton, S., et al. (2024) · New England Journal of Medicine · doi:10.1056/nejmoa2403664 · Cited by 440 · see citing works
Bennell, K. L., Ahamed, Y., Jull, G., Bryant, C., Hunt, M. A., Forbes, A. B., Kasza, J., Akram, M., Metcalf, B., Harris, A., et al. (2016) · Arthritis Care & Research · doi:10.1002/acr.22744 · Cited by 406 · see citing works
Salaffi, F., Leardini, G., Canesi, B., Mannoni, A., Fioravanti, A., Caporali, R., Lapadula, G., & Punzi, L. (2003) · Osteoarthritis and Cartilage · doi:10.1016/s1063-4584(03)00089-x · Cited by 331 · see citing works
Wallis, J. A., Webster, K. E., Levinger, P., & Taylor, N. F. (2013) · Osteoarthritis and Cartilage · doi:10.1016/j.joca.2013.08.003 · Cited by 328 · see citing works
Application of biomarkers in the development of drugs intended for the treatment of osteoarthritis
Kraus, V. B., Burnett, B., Coindreau, J., Cottrell, S., Eyre, D., Gendreau, M., Gardiner, J., Garnero, P., Hardin, J., Henrotin, Y., et al. (2011) · Osteoarthritis and Cartilage · doi:10.1016/j.joca.2010.08.019 · Cited by 328 · see citing works
Self-citationAquatic exercise for the treatment of knee and hip osteoarthritis
Bartels, E. M., Lund, H., Hagen, K. B., Dagfinrud, H., Christensen, R., & Danneskiold-Samsøe, B. (2007) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd005523.pub2 · Cited by 302 · see citing works
Chen, Z., Zhong, H., Wei, J., Lin, S., Zong, Z., Gong, F., Huang, X., Sun, J., Li, P., Lin, H., et al. (2019) · Arthritis Research & Therapy · doi:10.1186/s13075-019-2085-6 · Cited by 275 · see citing works
Petersen, K. K., Arendt-Nielsen, L., Simonsen, O., Wilder-Smith, O., & Laursen, M. B. (2015) · Pain · doi:10.1016/j.pain.0000000000000022 · Cited by 269 · see citing works
Development and validation of the Fibromyalgia Rapid Screening Tool (FiRST)
Perrot, S., Bouhassira, D., & Fermanian, J. (2010) · Pain · doi:10.1016/j.pain.2010.03.034 · Cited by 236 · see citing works
Wang, C., Schmid, C. H., Iversen, M. D., Harvey, W. F., Fielding, R. A., Driban, J. B., Price, L. L., Wong, J. B., Reid, K. F., Rones, R., et al. (2016) · Annals of Internal Medicine · doi:10.7326/m15-2143 · Cited by 206 · see citing works
Crotti, T. N., Smith, M. D., Weedon, H., Ahern, M. J., Findlay, D. M., Kraan, M., Tak, P. P., & Haynes, D. R. (2002) · Annals of the Rheumatic Diseases · doi:10.1136/ard.61.12.1047 · Cited by 186 · see citing works
de Rooij, M., van der Leeden, M., Heymans, M. W., Holla, J. F. M., Häkkinen, A., Lems, W. F., Roorda, L. D., Veenhof, C., Sanchez‐Ramirez, D. C., de Vet, H. C. W., et al. (2016) · Arthritis Care & Research · doi:10.1002/acr.22693 · Cited by 178 · see citing works
Homomorphic Encryption for Machine Learning in Medicine and Bioinformatics
Wood, A., Najarian, K., & Kahrobaei, D. (2021) · ACM Computing Surveys · doi:10.1145/3394658 · Cited by 179 · see citing works
Psychological profiles and pain characteristics of older adults with knee osteoarthritis
Cruz‐Almeida, Y., King, C. D., Goodin, B. R., Sibille, K. T., Glover, T. L., Riley, J. L., Sotolongo, A., Herbert, M. S., Schmidt, J., Fessler, B. J., et al. (2013) · Arthritis Care & Research · doi:10.1002/acr.22070 · Cited by 157 · see citing works
Haynes, D. R. (2003) · Rheumatology · doi:10.1093/rheumatology/keg047 · Cited by 157 · see citing works
Zhang, Q., Wu, J., Cao, Q., Xiao, L., Wang, L., He, D., Ouyang, G., Lin, J., Shen, B., Shi, Y., et al. (2009) · Arthritis & Rheumatism · doi:10.1002/art.24999 · Cited by 126 · see citing works
McDermott, M. M., Liu, K., Ferrucci, L., Tian, L., Guralnik, J. M., Liao, Y., & Criqui, M. H. (2011) · Journal of the American College of Cardiology · doi:10.1016/j.jacc.2010.09.053 · Cited by 122 · see citing works
Attur, M., Krasnokutsky, S., Statnikov, A., Samuels, J., Li, Z., Friese, O., Hellio Le Graverand‐Gastineau, M., Rybak, L., Kraus, V. B., Jordan, J. M., et al. (2015) · Arthritis & Rheumatology · doi:10.1002/art.39279 · Cited by 120 · see citing works
Hao, H. Q., Zhang, J. F., He, Q. Q., & Wang, Z. (2019) · Osteoarthritis and Cartilage · doi:10.1016/j.joca.2018.10.009 · Cited by 118 · see citing works
Mitochondrial DNA haplogroups: Role in the prevalence and severity of knee osteoarthritis
Rego‐Pérez, I., Fernández‐Moreno, M., Fernández‐López, C., Arenas, J., & Blanco, F. J. (2008) · Arthritis & Rheumatism · doi:10.1002/art.23659 · Cited by 109 · see citing works
Sutton, A. J., Muir, K. R., Mockett, S., & Fentem, P. (2001) · Annals of the Rheumatic Diseases · doi:10.1136/ard.60.8.756 · Cited by 101 · see citing works
Honorati, M. C., Meliconi, R., Pulsatelli, L., Canè, S., Frizziero, L., & Facchini, A. (2001) · Rheumatology · doi:10.1093/rheumatology/40.5.522 · Cited by 99 · see citing works
Yoga in Sedentary Adults with Arthritis: Effects of a Randomized Controlled Pragmatic Trial
Moonaz, S. H., Bingham, C. O., Wissow, L., & Bartlett, S. J. (2015) · The Journal of Rheumatology · doi:10.3899/jrheum.141129 · Cited by 98 · see citing works
Degenerative meniscus tears and mobility impairment in women with knee osteoarthritis
Lange, A. K., Fiatarone Singh, M. A., Smith, R. M., Foroughi, N., Baker, M. K., Shnier, R., & Vanwanseele, B. (2007) · Osteoarthritis and Cartilage · doi:10.1016/j.joca.2006.11.004 · Cited by 81 · see citing works
Leg symptom categories and rates of mobility decline in peripheral arterial disease
McDermott, M. M., Ferrucci, L., Liu, K., Guralnik, J. M., Tian, L., Liao, Y., & Criqui, M. H. (2010) · Journal of the American Geriatrics Society · doi:10.1111/j.1532-5415.2010.02941.x · Cited by 90 · see citing works
Faour, W. H., Mancini, A., He, Q. W., & Di Battista, J. A. (2003) · Journal of Biological Chemistry · doi:10.1074/jbc.m212790200 · Cited by 86 · see citing works
Lugo, J. P., Saiyed, Z. M., Lau, F. C., Molina, J. P. L., Pakdaman, M. N., Shamie, A. N., & Udani, J. K. (2013) · Journal of the International Society of Sports Nutrition · doi:10.1186/1550-2783-10-48 · Cited by 82 · see citing works
Goodin, B. R., Pham, Q. T., Glover, T. L., Sotolongo, A., King, C. D., Sibille, K. T., Herbert, M. S., Cruz-Almeida, Y., Sanden, S. H., Staud, R., et al. (2013) · Health Psychology · doi:10.1037/a0031592 · Cited by 79 · see citing works
Chronic pain, perceived stress, and cellular aging: an exploratory study.
Sibille, K. T., Langaee, T., Burkley, B., Gong, Y., Glover, T. L., King, C., Riley, J. L., Leeuwenburgh, C., Staud, R., Bradley, L. A., et al. (2012) · Molecular Pain · doi:10.1186/1744-8069-8-12 · Cited by 80 · see citing works
Bliddal, H., & Christensen, R. (2006) · Obesity Reviews · doi:10.1111/j.1467-789x.2006.00252.x · Cited by 78 · see citing works
Gui, H., Liu, X., Wang, Z.-W., He, D.-Y., Su, D.-F., & Dai, S.-M. (2014) · Rheumatology · doi:10.1093/rheumatology/ket447 · Cited by 76 · see citing works
Brown, C. A., El‐Deredy, W., & Jones, A. K. P. (2014) · European Journal of Neuroscience · doi:10.1111/ejn.12420 · Cited by 71 · see citing works
Li, L. C., Sayre, E. C., Xie, H., Clayton, C., & Feehan, L. M. (2017) · JMIR mHealth and uHealth · doi:10.2196/mhealth.7863 · Cited by 74 · see citing works
Miyazawa, K., Mori, A., Yamamoto, K., & Okudaira, H. (1998) · Journal of Biological Chemistry · doi:10.1074/jbc.273.13.7620 · Cited by 69 · see citing works
Finan, P. H., Quartana, P. J., & Smith, M. T. (2013) · Psychosomatic Medicine · doi:10.1097/psy.0b013e31828ef1d6 · Cited by 65 · see citing works
Sibille, K. T., Chen, H., Bartley, E. J., Riley, J., Glover, T. L., King, C. D., Zhang, H., Cruz-Almeida, Y., Goodin, B. R., Sotolongo, A., et al. (2017) · PAIN Reports · doi:10.1097/pr9.0000000000000591 · Cited by 63 · see citing works
Walsh, D. A., Catravas, J., & Wharton, J. (2000) · Annals of the Rheumatic Diseases · doi:10.1136/ard.59.2.125 · Cited by 57 · see citing works
Plaque composition in the proximal superficial femoral artery and peripheral artery disease events
McDermott, M. M., Kramer, C. M., Tian, L., Carr, J., Guralnik, J. M., Polonsky, T., Carroll, T., Kibbe, M., Criqui, M. H., Ferrucci, L., et al. (2017) · JACC: Cardiovascular Imaging · doi:10.1016/j.jcmg.2016.08.012 · Cited by 55 · see citing works
Rucker‐Whitaker, C., Greenland, P., Liu, K., Chan, C., Guralnik, J. M., Criqui, M. H., Taylor, L., Pearce, W. H., & McGraeMcDermott, M. (2004) · Journal of the American Geriatrics Society · doi:10.1111/j.1532-5415.2004.52259.x · Cited by 52 · see citing works
Habib, G., Jabbour, A., Artul, S., & Hakim, G. (2014) · Clinical Rheumatology · doi:10.1007/s10067-013-2374-4 · Cited by 52 · see citing works
mtDNA haplogroups and osteoarthritis in different geographic populations
Soto-Hermida, A., Fernández-Moreno, M., Oreiro, N., Fernández-López, C., Rego-Pérez, I., & Blanco, F. J. (2014) · Mitochondrion · doi:10.1016/j.mito.2014.03.001 · Cited by 51 · see citing works
Marra, C. A., Cibere, J., Tsuyuki, R. T., Soon, J. A., Esdaile, J. M., Gastonguay, L., Oteng, B., Embley, P., Colley, L., Enenajor, G., et al. (2007) · Arthritis Care & Research · doi:10.1002/art.23019 · Cited by 48 · see citing works
Lamas, J. R., Rodríguez-Rodríguez, L., Vigo, A. G., Álvarez-Lafuente, R., López-Romero, P., Marco, F., Camafeita, E., Dopazo, A., Callejas, S., Villafuertes, E., et al. (2010) · Annals of the Rheumatic Diseases · doi:10.1136/ard.2009.122564 · Cited by 43 · see citing works
TNF-α-induced aquaporin 9 in synoviocytes from patients with OA and RA
Nagahara, M., Waguri-Nagaya, Y., Yamagami, T., Aoyama, M., Tada, T., Inoue, K., Asai, K., & Otsuka, T. (2010) · Rheumatology · doi:10.1093/rheumatology/keq028 · Cited by 36 · see citing works
McDermott, M. M., Polonsky, T. S., Kibbe, M. R., Tian, L., Zhao, L., Pearce, W. H., Gao, Y., & Guralnik, J. M. (2017) · Journal of Vascular Surgery · doi:10.1016/j.jvs.2017.02.037 · Cited by 36 · see citing works
Bossen, D., Kloek, C., Snippe, H. W., Dekker, J., de Bakker, D., & Veenhof, C. (2016) · JMIR Research Protocols · doi:10.2196/resprot.5049 · Cited by 30 · see citing works
Smittenaar, P., Erhart-Hledik, J. C., Kinsella, R., Hunter, S., Mecklenburg, G., & Perez, D. (2017) · JMIR Rehabilitation and Assistive Technologies · doi:10.2196/rehab.7258 · Cited by 34 · see citing works
Bonfante, H. D. L., Almeida, C. D. S., Abramo, C., Grunewald, S. T. F., Levy, R. A., & Teixeira, H. C. (2017) · International Journal of Rheumatic Diseases · doi:10.1111/1756-185x.12589 · Cited by 33 · see citing works
Feng, J., Li, Z., Tian, L., Mu, P., Hu, Y., Xiong, F., & Ma, X. (2022) · BMC Complementary Medicine and Therapies · doi:10.1186/s12906-022-03740-9 · Cited by 33 · see citing works
Kim, T. W., Chang, M. J., Shin, C. Y., Chang, C. B., & Kang, S.-B. (2023) · Scientific Reports · doi:10.1038/s41598-023-35982-z · Cited by 24 · see citing works
Habib, G., Khazin, F., Jabbour, A., Chernin, M., Badarny, S., Hakim, J., & Artul, S. (2014) · Journal of Investigative Medicine · doi:10.2310/jim.0000000000000048 · Cited by 21 · see citing works
Lee, S. Y., Park, S.-H., Lee, S. W., Lee, S. H., Son, M. K., Choi, Y. H., Chung, W. T., & Yoo, Y. H. (2014) · Archives of Pharmacal Research · doi:10.1007/s12272-014-0365-x · Cited by 17 · see citing works
Prizov, A., Tchetina, E., Eremin, I., Zagorodniy, N., Pulin, A., Belyak, E., Goncharov, E., Kotenko, K., Smyshlyaev, I., Glukhova, S., et al. (2022) · International Journal of Molecular Sciences · doi:10.3390/ijms232112835 · Cited by 16 · see citing works
Hatfield, G. L., Costello, K. E., Astephen Wilson, J. L., Stanish, W. D., & Hubley-Kozey, C. L. (2021) · Archives of Physical Medicine and Rehabilitation · doi:10.1016/j.apmr.2021.03.038 · Cited by 15 · see citing works
Mace, R. A., Greenberg, J., Lemaster, N., Duarte, B., Penn, T., Kanaya, M., Doorley, J. D., Burris, J. L., Jacobs, C. A., & Vranceanu, A.-M. (2022) · JMIR Formative Research · doi:10.2196/34654 · Cited by 15 · see citing works
“The inclusion criteria were as follows: (1) obesity (BMI ≥30 kg/m(2)), (2) idiopathic KOA [49] with mild to moderate radiographic changes (Kellgren or Lawrence grade 2 or 3 [50]) or Knee Injury and Osteoarthritis Outcome Scores (KOOSs) consistent with KOA [51], (3) elevated depressive symptoms with a 9-item Patient He…”
BackgroundPuts, S., Njemini, R., Bilterys, T., Lefeber, N., Scheerlinck, T., Nijs, J., Beckwée, D., & Bautmans, I. (2024) · Journal of Clinical Medicine · doi:10.3390/jcm13175212 · Cited by 15 · see citing works
Waszczykowski, M., Fabiś-Strobin, A., Bednarski, I., Lesiak, A., Narbutt, J., & Fabiś, J. (2020) · Diagnostics · doi:10.3390/diagnostics11010052 · Cited by 9 · see citing works
Tamin, T. Z., & Clements, C. (2025) · Acta Medica Indonesiana
- Authors
- Altman, R., Asch, E., Bloch, D., Bole, G., Borenstein, D., Brandt, K., Christy, W., Cooke, T. D., Greenwald, R., Hochberg, M., Howell, D., Kaplan, D., Koopman, W., Longley, S., Mankin, H., McShane, D. J., Medsger, T., Meenan, R., Mikkelsen, W., Moskowitz, R., Murphy, W., Rothschild, B., Segal, M., Sokoloff, L., & Wolfe, F.
- Affiliations
- University of Miami (US)
- New York University (US)
- Stanford University (US)
- University of Michigan (US)
- George Washington University (US)
- Indiana University Bloomington (US)
- University of Pittsburgh (US)
- Queen's University (CA)
- Northwell Health (US)
- Johns Hopkins University (US)
- SUNY Downstate Health Sciences University (US)
- University of Alabama at Birmingham (US)
- University of Florida (US)
- Harvard University (US)
- Boston University (US)
- Case Western Reserve University (US)
- Washington University in St. Louis (US)
- Menorah Medical Center (US)
- Stony Brook University (US)
- University of Kansas (US)
- Corresponding author
- Altman, R.
- ORCID
- Venue
- Arthritis & Rheumatism
- Publisher
- Wiley
- Published
- 1986-08
- Volume
- 29
- Issue
- 8
- Pages
- 1039-1049
- ISSN
- 0004-3591 (ISSN-L)
- 1529-0131
- OpenAlex
- W2058147305
- Cited by
- 6,777
- References
- 12
- Citations by year
- 2026: 194 · 2025: 242 · 2024: 253 · 2023: 303 · 2022: 316 · 2021: 374 · 2020: 347 · 2019: 288 · 2018: 312 · 2017: 320 · 2016: 302 · 2015: 306 · 2014: 300 · 2013: 305 · 2012: 249
- FWCI
- 13.43
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Arthritis & Rheumatism (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Rheumatology › Osteoarthritis Treatment and Mechanisms
- Health Sciences › Medicine › Pharmacology › Musculoskeletal pain and rehabilitation
- Health Sciences › Medicine › Surgery › Hip disorders and treatments
- Keywords
- knee osteoarthritis, osteoarthritis classification, clinical classification criteria, idiopathic osteoarthritis, secondary osteoarthritis, rheumatoid arthritis, classification trees, diagnostic algorithm, radiographic evaluation, clinical history and physical examination
- MeSH terms
- Adult, Age Factors, Female, Humans, Knee Joint, Male, Middle Aged, Movement, Osteoarthritis, Pain, Radiography
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review