Cost-effectiveness of Self-management Methods for the Treatment of Chronic Pain in an Aging Adult Population: A Systematic Review of the Literature
Abstract
OBJECTIVE: To determine the cost-effectiveness of self-management techniques for older populations (65 and over) with chronic pain and in the absence of such evidence to investigate this question in an aging adult population (average age 60 and over). METHODS: Systematic review of randomized controlled trials (RCTs) with cost-effectiveness data and at least 6 months' follow-up, up to December 2010. RESULTS: No RCT studies reported cost-effectiveness of self-management exclusively in the over 65 age group. Ten RCTs reported participants with an average age of 60 years or over and met all other inclusion criteria. All of these studies measured cost-effectiveness as cost per improvement in primary outcome, 7 of them using the Western Ontario and McMaster Universities Osteoarthritis Index score, of which 6 reported the pain dimension. Six studies reported cost per quality-adjusted life year (QALY)-gained information, with a further 1 reporting EQ-5D. In 7 studies, relative to usual care, self-management was effective, and in the remaining 3 studies, there was no significant difference. Among those reporting cost per QALY-gained results, self-management did not lead to statistically significant QALY gains relative to usual care (with only one exception). Eight studies suggested that the cost of developing and delivering self-management interventions may be partly offset by savings from reduced subsequent health care resource use. CONCLUSIONS: Self-management is effective among an aging adult population (mean age over 60) with chronic pain and may be cost-effective when outcomes are measured using the Western Ontario and McMaster Universities Osteoarthritis Index pain score. Cost-effectiveness is less certain when measured using the QALY metric. Uncertainty over conclusions regarding cost-effectiveness exists partly due to lack of information regarding societal willingness to pay for pain improvement. There is a need for large multicentred high-quality RCTs to confirm the findings of this review exclusively among older aged populations, such as those who have already reached the statutory retirement age.
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?
Self-management is effective and potentially cost-effective in improving pain among an older adult population.
“Boyers et al. determined that self-management is effective and potentially cost-effective in improving pain among an older adult population, though noted that further research was required [52].”
From Identification and Management of Chronic Pain in Primary Care: a Review (2016) · cites this paper as [52]
Cites
EuroQol: a new facility for the measurement of health-related quality of life
(1990) · Health Policy · doi:10.1016/0168-8510(90)90421-9 · Cited by 15,736 · see citing works
Methods for the Economic Evaluation of Health Care Programmes
Drummond, M. E., Sculpher, M. J., Torrance, G. W., O’Brien, B. J., & Stoddart, G. L. (2005) · doi:10.1093/oso/9780198529446.001.0001 · Cited by 13,648 · see citing works
Classification of Chronic Pain: Descriptions of Chronic Pain Syndromes and Definitions of Pain Terms
Merskey, H. (1994) · Medical Entomology and Zoology · Cited by 3,362 · see citing works
The economic burden of back pain in the UK
Maniadakis, N., & Gray, A. (2000) · Pain · doi:10.1016/s0304-3959(99)00187-6 · Cited by 1,510 · see citing works
Representing uncertainty: the role of cost‐effectiveness acceptability curves
Fenwick, E. A. L., Claxton, K., & Sculpher, M. J. (2001) · Health Economics · doi:10.1002/hec.635 · Cited by 1,112 · see citing works
Wall and Melzack's Textbook of Pain
McMahon, S. B., & Koltzenburg, M. (2005) · Cited by 1,014 · see citing works
Economic Evaluation in Clinical Trials
Glick, H. A., Doshi, J. A., Sonnad, S. S., & Polsky, D. E. (2014) · Oxford University Press eBooks · doi:10.1093/med/9780199685028.001.0001 · Cited by 910 · see citing works
Hurst, N. P., Kind, P., Ruta, D. A., Hunter, M., & Stubbings, A. (1997) · Lara D. Veeken · doi:10.1093/rheumatology/36.5.551 · Cited by 825 · see citing works
The impact of chronic pain in the community.
Smith, B. H., Elliott, A. M., Chambers, W. A., Smith, W. C., Hannaford, P. C., & Penny, K. (2001) · Family Practice · doi:10.1093/fampra/18.3.292 · Cited by 540 · see citing works
Self-citationThomas, E., Peat, G., Harris, L. K., Wilkie, R., & Croft, P. R. (2004) · Pain · doi:10.1016/j.pain.2004.04.017 · Cited by 507 · see citing works
Handling uncertainty when performing economic evaluation of healthcare interventions.
Briggs, A. H., & Gray, L. J. (1999) · Health Technology Assessment · doi:10.3310/hta3020 · Cited by 392 · see citing works
Neck and back pain : the scientific evidence of causes, diagnosis, and treatment
Jonsson, E., & NACHEMSON, A. L. (2000) · Medical Entomology and Zoology · Cited by 342 · see citing works
Cochrane, T., Davey, R., & Edwards, S. M. (2005) · Health Technology Assessment · doi:10.3310/hta9310 · Cited by 194 · see citing works
McCarthy, C. J., Mills, P., Pullen, R., Richardson, G. A., Hawkins, N., Roberts, C., Silman, A. J., & Oldham, J. A. (2004) · Health Technology Assessment · doi:10.3310/hta8460 · Cited by 170 · see citing works
Measurement of the quality of life in rheumatic disorders using the EuroQol.
Wolfe, F., & Hawley, D. J. (1997) · Lara D. Veeken · doi:10.1093/rheumatology/36.7.786 · Cited by 168 · see citing works
Jenkinson, C., Doherty, M., Avery, A. J., Read, A., Taylor, M. A., Sach, T., Silcocks, P. B. S., & Muir, K. R. (2009) · BMJ · doi:10.1136/bmj.b3170 · Cited by 150 · see citing works
Evenson, K. R., Rosamond, W. D., Cai, J., Roux, A. V. D., & Brancati, F. L. (2002) · American Journal of Epidemiology · doi:10.1093/aje/155.8.692 · Cited by 137 · see citing works
Weinberger, M., Tierney, W. M., Cowper, P. A., Katz, B. P., & Booher, P. (1993) · Arthritis & Rheumatism · doi:10.1002/art.1780360216 · Cited by 101 · see citing works
Jessep, S., Walsh, N. E., Ratcliffe, J., & Hurley, M. (2009) · Physiotherapy · doi:10.1016/j.physio.2009.01.005 · Cited by 100 · see citing works
Hurley, M. V., Walsh, N. E., Mitchell, H., Pimm, J., Williamson, E., Jones, R. H., Reeves, B. C., Dieppe, P. A., & Patel, A. K. (2007) · Arthritis Care & Research · doi:10.1002/art.23011 · Cited by 96 · see citing works
Barton, G., Sach, T., Jenkinson, C., Avery, A. J., Doherty, M., & Muir, K. R. (2008) · Health and Quality of Life Outcomes · doi:10.1186/1477-7525-6-51 · Cited by 85 · see citing works
And now for vertical equity? Some concerns arising from Aboriginal health in Australia
MOONEY, G. H. (1996) · Health Economics · doi:10.1002/(sici)1099-1050(199603)5:2 · Cited by 76 · see citing works
The economic impact of musculoskeletal disorders
Lee, P. (1994) · Quality of Life Research · doi:10.1007/bf00433381 · Cited by 73 · see citing works
Cost-effectiveness of aerobic and resistance exercise in seniors with knee osteoarthritis
Sevick, M. A., Bradham, D. D., Muender, M. M., Chen, G. J., Enarson, C. E., Dailey, M., & Ettinger, W. H. (2000) · Medicine & Science in Sports & Exercise · doi:10.1097/00005768-200009000-00002 · Cited by 73 · see citing works
Acute versus chronic pain treatment in Alzheimer's disease
Pickering, G. P., Jourdan, D., & Dubray, C. (2005) · European Journal of Pain · doi:10.1016/j.ejpain.2005.06.010 · Cited by 71 · see citing works
Onder, G., Cesari, M., Russo, A., Zamboni, V., Bernabei, R., & Landi, F. (2006) · Pain · doi:10.1016/j.pain.2005.12.003 · Cited by 63 · see citing works
Social networks and pain interference with daily activities in middle and old age
Peat, G., Thomas, E., Handy, J., & Croft, P. R. (2004) · Pain · doi:10.1016/j.pain.2004.09.029 · Cited by 61 · see citing works
Cost effectiveness of a two-year home exercise program for the treatment of knee pain
Thomas, K. S., Miller, P., Doherty, M., Muir, K. R., Jones, A. C., & O'Reilly, S. C. (2005) · Arthritis & Rheumatism · doi:10.1002/art.21173 · Cited by 60 · see citing works
Coupé, V. M. H., Veenhof, C., van Tulder, M. W., Dekker, J., Bijlsma, J. W. J., & van den Ende, C. H. M. (2006) · Annals of the Rheumatic Diseases · doi:10.1136/ard.2006.054478 · Cited by 54 · see citing works
Belsey, J. (2002) · Journal of Medical Economics · doi:10.3111/200205039050 · Cited by 50 · see citing works
Economic evaluation of arthritis self management in primary care
Patel, A. K., Buszewicz, M., Beecham, J. K., Griffin, M., Rait, G., Nazareth, I., Atkinson, A., Barlow, J., & Haines, A. (2009) · BMJ · doi:10.1136/bmj.b3532 · Cited by 48 · see citing works
The assessment of pain in older people
Collett, B., O'Mahoney, S., Schofield, P., Closs, S. J., & Potter, J. (2007) · Clinical Medicine · doi:10.7861/clinmedicine.7-5-496 · Cited by 42 · see citing works
Self-citationBarton, G., Sach, T., Jenkinson, C., Doherty, M., Avery, A. J., & Muir, K. R. (2009) · BMJ · doi:10.1136/bmj.b2273 · Cited by 30 · see citing works
Management of pain in patients with multiple health problems: a guide for the practicing physician
RUOFF, G. E. (1998) · The American Journal of Medicine · doi:10.1016/s0002-9343(98)00074-6 · Cited by 25 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Identification and Management of Chronic Pain in Primary Care: a Review
Mills, S., Torrance, N., & Smith, B. H. (2016) · Current Psychiatry Reports · doi:10.1007/s11920-015-0659-9 · Cited by 216 · see citing works
Self-citationThe effect of chronic pain on life satisfaction: Evidence from Australian data
McNamee, P., & Mendolia, S. (2014) · Social Science & Medicine · doi:10.1016/j.socscimed.2014.09.019 · Cited by 119 · see citing works
Self-citationSystematic overview of economic evaluations of health-related rehabilitation
Wilsher, S. H., Irvine, L., Fan, H. D., Shakespeare, T., Suhrcke, M., Horton, S., Poland, F. M., Hooper, L., & Song, F. (2015) · Disability and health journal · doi:10.1016/j.dhjo.2015.08.009 · Cited by 92 · see citing works
Damush, T. M., Kroenke, K., Bair, M. J., Wu, J., Tu, W., Krebs, E. E., & Poleshuck, E. L. (2016) · European Journal of Pain · doi:10.1002/ejp.830 · Cited by 93 · see citing works
Empowering Patients with Persistent Pain Using an Internet-based Self-Management Program
Wilson, M., Roll, J. M., Corbett, C., & Barbosa-Leiker, C. (2015) · Pain Management Nursing · doi:10.1016/j.pmn.2014.09.009 · Cited by 83 · see citing works
Vugts, M. A. P., Joosen, M. C. W., van der Geer, J. E., Zedlitz, A. M. E. E., & Vrijhoef, H. J. M. (2018) · PLOS ONE · doi:10.1371/journal.pone.0196467 · Cited by 85 · see citing works
Mirror therapy: A potential intervention for pain management
Wittkopf, P. G., & Johnson, M. I. (2017) · Revista da Associação Médica Brasileira · doi:10.1590/1806-9282.63.11.1000 · Cited by 72 · see citing works
Barriers to self-management of chronic pain in primary care: a qualitative focus group study
Gordon, K., Rice, H., Allcock, N., Bell, P., Dunbar, M., Gilbert, S., & Wallace, H. (2016) · British Journal of General Practice · doi:10.3399/bjgp17x688825 · Cited by 65 · see citing works
Mínguez, D. R., Kowalski, M., Odena, M. V., Pontzen, D. L., Kadić, A. J., Jerić, M., Došenović, S., Jakus, D., Vrdoljak, M., Peričić, T. P., et al. (2017) · Anesthesia & Analgesia · doi:10.1213/ane.0000000000002227 · Cited by 56 · see citing works
Kechichian, A., Lafrance, S., Matifat, E., Dubé, F., Lussier, D., Benhaim, P., Perreault, K., Filiatrault, J., Rainville, P., Higgins, J., et al. (2020) · Journal of Geriatric Physical Therapy · doi:10.1519/jpt.0000000000000279 · Cited by 54 · see citing works
A systematic review of the association between health literacy and pain self-management
Kim, K., Yang, Y., Wang, Z., Chen, J., Barandouzi, Z. A., Hong, H., Han, H.-R., & Starkweather, A. R. (2021) · Patient Education and Counseling · doi:10.1016/j.pec.2021.09.037 · Cited by 49 · see citing works
Rangan, G. K., Alexander, S. I., Campbell, K. L., Dexter, M. A. J., Lee, V. W., Lopez‐Vargas, P. A., Mai, J., Mallett, A. J., Patel, C., Patel, M. I., et al. (2015) · Nephrology · doi:10.1111/nep.12658 · Cited by 47 · see citing works
Bürge, E., Monnin, D., Berchtold, A., & Allet, L. (2016) · Physical Therapy · doi:10.2522/ptj.20140333 · Cited by 44 · see citing works
Kroenke, K., Baye, F. M., Lourens, S. G., Evans, E., Weitlauf, S., McCalley, S., Porter, B. W., Matthias, M. S., & Bair, M. J. (2019) · Journal of General Internal Medicine · doi:10.1007/s11606-019-05121-4 · Cited by 39 · see citing works
The Landscape of Chronic Pain: Broader Perspectives
Johnson, M. I. (2019) · Medicina · doi:10.3390/medicina55050182 · Cited by 38 · see citing works
Cooper, K., Schofield, P., Klein, S., Smith, B. H., & Jehu, L. M. (2016) · Physiotherapy · doi:10.1016/j.physio.2016.05.005 · Cited by 33 · see citing works
Self-citationCan service integration work for universal health coverage? Evidence from around the globe
Lê, G., Morgan, R., Bestall, J., Featherstone, I., Veale, T., & Ensor, T. (2016) · Health Policy · doi:10.1016/j.healthpol.2016.02.007 · Cited by 30 · see citing works
Pain assessment in elderly with dementia: Brazilian validation of the PACSLAC scale
Thé, K. B., Gazoni, F. M., Cherpak, G. L., Lorenzet, I. C., dos Santos, L. A., Nardes, E. M., & Santos, F. C. (2016) · Einstein (São Paulo) · doi:10.1590/s1679-45082016ao3628 · Cited by 27 · see citing works
Fu, Y., McNichol, E., Marczewski, K., & Closs, S. J. (2018) · Qualitative Health Research · doi:10.1177/1049732318768229 · Cited by 24 · see citing works
Mallik, A. K., Pandey, S., Srivastava, A., Kumar, S., & Kumar, A. (2020) · Archives of Rehabilitation Research and Clinical Translation · doi:10.1016/j.arrct.2020.100081 · Cited by 23 · see citing works
Cost-effectiveness of physical activity programs and services for older adults: a scoping review
Pinheiro, M. B., Howard, K., Oliveira, J. S., Kwok, W. S., Tiedemann, A., Wang, B., Taylor, J., Bauman, A. E., & Sherrington, C. (2023) · Age and Ageing · doi:10.1093/ageing/afad023 · Cited by 22 · see citing works
Morales‐Fernandez, A., Morales‐Asencio, J. M., Canca‐Sanchez, J. C., Moreno‐Martin, G., Vergara‐Romero, M., & Group for pain management Hospital Costa del Sol Members (2016) · Journal of Advanced Nursing · doi:10.1111/jan.12908 · Cited by 19 · see citing works
Antunes, M. D., Loures, F. C. N. D. R., de Souza, I. M. B., Cruz, A. T., Januário, P. D. O., Pinheiro, M. M. L. S., Schmitt, A. C. B., Frutos‐Bernal, E., Nogueras, A. M. M., & Marques, A. P. (2023) · Trials · doi:10.1186/s13063-023-07588-3 · Cited by 19 · see citing works
Courtney, R. E., Schadegg, M. J., Bolton, R. E., Smith, S., & Harden, S. M. (2023) · Pain Management Nursing · doi:10.1016/j.pmn.2023.09.010 · Cited by 15 · see citing works
Gustavsson, C., & von Koch, L. (2016) · Journal of Pain Research · doi:10.2147/jpr.s125074 · Cited by 13 · see citing works
Chronic Pain Self-Management Program for Low-Income Patients: Themes from a Qualitative Inquiry
Turner, B. J., Rodriguez, N., Bobadilla, R., Hernández, A. E., & Yin, Z. (2018) · Pain Medicine · doi:10.1093/pm/pny192 · Cited by 12 · see citing works
Ortiz, L., & Velasco, M. (2017) · Revista Médica Clínica Las Condes · doi:10.1016/j.rmclc.2017.10.008 · Cited by 11 · see citing works
Level of readiness of chronic pain patients to practise active self‐care
Scala, E., Décosterd, I., Faouzi, M., Burnand, B., & Rodondi, P. (2018) · European Journal of Pain · doi:10.1002/ejp.1276 · Cited by 10 · see citing works
Nemati, D., Hinrichs, R., Johnson, A. J., Lauche, R., & Munk, N. (2023) · Journal of Integrative and Complementary Medicine · doi:10.1089/jicm.2023.0271 · Cited by 9 · see citing works
Magnussen, H. J., Kjeken, I., Pinxsterhuis, I., Sjøvold, T. A., Hennig, T., Thorsen, E., & Feiring, M. (2023) · Health Expectations · doi:10.1111/hex.13744 · Cited by 8 · see citing works
The Role of Integrated Care in Managing Chronic Pain
Leasure, W. B., & Leasure, E. L. (2017) · FOCUS The Journal of Lifelong Learning in Psychiatry · doi:10.1176/appi.focus.20170014 · Cited by 10 · see citing works
Telecare management of pain and mood symptoms: Adherence, utility, and patient satisfaction
Bushey, M. A., Kroenke, K., Weiner, J., Porter, B. W., Evans, E., Baye, F. M., Lourens, S. G., & Weitlauf, S. (2019) · Journal of Telemedicine and Telecare · doi:10.1177/1357633x19856156 · Cited by 7 · see citing works
KHA-CARI Autosomal Dominant Polycystic Kidney Disease Guideline: Psychosocial Care
Tong, A., Mallett, A. J., Lopez‐Vargas, P. A., & Rangan, G. K. (2015) · Seminars in Nephrology · doi:10.1016/j.semnephrol.2015.10.010 · Cited by 6 · see citing works
Winhusen, T. M., Wilson, M., Dolor, R. J., Theobald, J., Lewis, D. F., Regan, S. L., & Meulen, M. B. V. (2020) · Contemporary Clinical Trials · doi:10.1016/j.cct.2020.106245 · Cited by 6 · see citing works
Evidence Brief: Developing a National Pain Strategy for Canada
Waddell, K., Moat, K. A., & Lavis, J. N. (2017) · MacSphere (McMaster University) · Cited by 5 · see citing works
Baroni, M. P., Hespanhol, L., Miyamoto, G. C., Daniel, C. R., Fernandes, L. G., dos Reis, F. J. J., Pate, J. W., & Saragiotto, B. T. (2023) · BMC Musculoskeletal Disorders · doi:10.1186/s12891-023-06360-7 · Cited by 4 · see citing works
Factors affecting the effectiveness of ‘ruqyah’ treatment among Muslim community in Malaysia
Omar, M., Abdullah, M., Ahmad, A. R., Amin, A. R. M., Shafei, S. A., Haron, S., Ramli, R., Hussian, M. A., Kusmin, Z. A., Haron, H., et al. (2024) · Journal of Spirituality in Mental Health · doi:10.1080/19349637.2024.2338839 · Cited by 4 · see citing works
Thành, N. X., Lopatina, E., Montgomery, L. S., Robert, M., Tanguay, R. L., & Wasylak, T. (2023) · British Journal of Pain · doi:10.1177/20494637231209928 · Cited by 4 · see citing works
Design and evaluation of mobile scenario based learning in the self-management of chronic pain
Koulas, I., Billis, A. S., Kousouri, N., Vasilopoulos, V., Lykotsetas, E., Kola, D., Dafli, E., Spachos, D., & Bamidis, P. D. (2021) · Health Informatics Journal · doi:10.1177/1460458220977575 · Cited by 3 · see citing works
A Typology of Future Health Services by Exploring Core Concepts and Values
Kim, J., Piao, M., Byun, A., & Lee, J. (2018) · CIN Computers Informatics Nursing · doi:10.1097/cin.0000000000000488 · Cited by 3 · see citing works
Development and evaluation of a novel intervention for rehabilitation following whiplash injury
Wiangkham, T. (2017) · University of Birmingham Institutional Research Archive (University of Birmingham) · Cited by 3 · see citing works
Maatz, K. L., & Zimmerman, J. Q. (2014) · UND Scholarly Commons (University of North Dakota)
Kwaees, T. A. (2018) · CLOK (University of Central Lancashire)
Managing chronic pain in primary care
Mills, S. E. E., & Smith, B. H. (2022) · Wiley eBooks · doi:10.1002/9781119701170.ch13
Self-citationImpact of Health Education Program on Musculo Skeletal Problems among School Teachers in Rural Areas
Pathi, M., Deshpande, S., Gazbare, P. S., & Palekar, T. J. K. (2022) · International Journal of Musculoskeletal Pain Prevention · doi:10.52547/ijmpp.7.3.765
What is available to support pain management in Parkinson’s: a scoping review protocol
Parkinson, M., Ryan, C. G., Avery, L., Hand, A., Ramaswamy, B., Jones, J., Lindop, F., Silverdale, M., Baker, K., & Naisby, J. (2023) · International Journal for Equity in Health · doi:10.1186/s12939-023-02046-7
- Authors
- Boyers, D., McNamee, P., Clarke, A., Jones, D., Martin, D., Schofield, P., & Smith, B. H.
- Affiliations
- University of Aberdeen (GB)
- Northumbria University (GB)
- Teesside University (GB)
- University of Dundee (GB)
- Corresponding author
- Boyers, Dwayne
- McNamee, Paul
- Venue
- The Clinical Journal of Pain
- Published
- 2013-04
- Volume
- 29
- Issue
- 4
- Pages
- 366-375
- ISSN
- 0749-8047 (ISSN-L)
- OpenAlex
- W2116570868
- Cited by
- 46
- References
- 34
- Citations by year
- 2024: 1 · 2023: 8 · 2022: 2 · 2021: 2 · 2020: 3 · 2019: 3 · 2018: 6 · 2017: 6 · 2016: 9 · 2015: 4 · 2014: 2
- FWCI
- 1.40
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Clinical Journal of Pain (publishedVersion)
- PubMed (publishedVersion)
- Discovery Research Portal (University of Dundee) (publishedVersion)
- Greenwich Academic Literature Archive (University of Greenwich) (submittedVersion)
- TeesRep (Teesside University) (submittedVersion)
- Funders
- Biotechnology and Biological Sciences Research Council
- Topics
- Health Sciences › Medicine › Pharmacology › Musculoskeletal pain and rehabilitation
- Social Sciences › Economics, Econometrics and Finance › Economics and Econometrics › Health Systems, Economic Evaluations, Quality of Life
- Health Sciences › Medicine › Anesthesiology and Pain Medicine › Pain Management and Opioid Use
- Keywords
- self-management, chronic pain, older adults, cost-effectiveness, osteoarthritis, Western Ontario and McMaster Universities Osteoarthritis Index, quality-adjusted life years, EQ-5D, health care utilization, pain management
- MeSH terms
- Aged, Aged, 80 and over, Aging, Cost-Benefit Analysis, Humans, Middle Aged, Self Care, Quality-Adjusted Life Years, Chronic Pain, Pain Management
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