The Unit of Analysis Error in Studies About Physicians' Patient Care Behavior

Overview

Journal J Gen Intern Med

Publisher Springer

Specialty General Medicine

Date 1992 Nov 1

PMID 1453246

Citations 255

Authors

G W Divine

J T Brown

L M FRAZIER

Affiliations

Soon will be listed here.

Abstract

Objective: To estimate the frequency with which patients are incorrectly used as the unit of analysis among statistical calculations in published studies of physicians' patient care behavior.

Design: Retrospective review of studies published during 1980-1990. ARTICLES: 54 articles retrieved by a computerized search using medical subject headings for physicians and study characteristics. Article selection criteria included the requirement that the physician should have been the correct unit of analysis.

Intervention: Presence of the error was determined by consensus using published criteria.

Main Results: The error was present in 38 articles (70%). The number of study physicians was reported in 35 articles (65%). The error was found in 57% of articles that reported the number of study physicians and in 95% of those that did not. The error rate was not lower among articles published more recently nor among those published in journals with higher rates of article citations in the medical literature.

Conclusion: The unit of analysis error occurs frequently and can generate artificially low p values. Failure to report the number of study physicians can be a clue that this type of error has been made.

Citing Articles

Antidepressants versus placebo for generalised anxiety disorder (GAD).

Kopcalic K, Arcaro J, Pinto A, Ali S, Barbui C, Curatoli C Cochrane Database Syst Rev. 2025; 1:CD012942.

PMID: 39880377 PMC: 11779548. DOI: 10.1002/14651858.CD012942.pub2.

Family-based interventions versus standard care for people with schizophrenia.

Chien W, Ma D, Bressington D, Mou H Cochrane Database Syst Rev. 2024; 10:CD013541.

PMID: 39364773 PMC: 11450935. DOI: 10.1002/14651858.CD013541.pub2.

Transitional discharge interventions for people with schizophrenia.

Roson Rodriguez P, Chen X, Arancibia M, Garegnani L, Escobar Liquitay C, Mohammad H Cochrane Database Syst Rev. 2024; 8:CD009788.

PMID: 39212182 PMC: 11363221. DOI: 10.1002/14651858.CD009788.pub3.

Haloperidol (oral) versus olanzapine (oral) for people with schizophrenia and schizophrenia-spectrum disorders.

Ibragimov K, Keane G, Carreno Glaria C, Cheng J, Llosa A Cochrane Database Syst Rev. 2024; 7:CD013425.

PMID: 38958149 PMC: 11220909. DOI: 10.1002/14651858.CD013425.pub2.

Collaborative care approaches for people with severe mental illness.

Reilly S, Hobson-Merrett C, Gibbons B, Jones B, Richards D, Plappert H Cochrane Database Syst Rev. 2024; 5:CD009531.

PMID: 38712709 PMC: 11075124. DOI: 10.1002/14651858.CD009531.pub3.

References

Cohen D, Berner U, Dubach U . Physician compliance in the management of hypertensive patients. J Hypertens Suppl. 1985; 3(1):S73-6. View

Palmer R, Louis T, HSU L, Peterson H, Rothrock J, Strain R . A randomized controlled trial of quality assurance in sixteen ambulatory care practices. Med Care. 1985; 23(6):751-70. DOI: 10.1097/00005650-198506000-00001. View

Dusitsin N, Chalapati S, Varakamin S, Boonsiri B, Ningsanon P, Gray R . Post-partum tubal ligation by nurse-midwives and doctors in Thailand. Lancet. 1980; 1(8169):638-9. DOI: 10.1016/s0140-6736(80)91129-0. View

Copeman R, Swannell R, Pincus D, Woodhead K . Utilization of the "Smokescreen" smoking-cessation programme by general practitioners and their patients. Med J Aust. 1989; 151(2):83-7. DOI: 10.5694/j.1326-5377.1989.tb101167.x. View

Reid A, Carroll J, Ruderman J, Murray M . Differences in intrapartum obstetric care provided to women at low risk by family physicians and obstetricians. CMAJ. 1989; 140(6):625-33. PMC: 1268752. View

Cohen S, Stookey G, Katz B, Drook C, Smith D . Encouraging primary care physicians to help smokers quit. A randomized, controlled trial. Ann Intern Med. 1989; 110(8):648-52. DOI: 10.7326/0003-4819-110-8-648. View

Eisenberg J, Williams S . Limited usefulness of the proportion of tests with normal results in review of diagnostic services utilization. Clin Chem. 1983; 29(12):2111-3. View

Chaska B, Mellstrom M, Grambsch P, Nesse R . Influence of site of obstetric care and delivery on pregnancy management and outcome. J Am Board Fam Pract. 1988; 1(3):152-63. View

Wallenstein S, Zucker C, Fleiss J . Some statistical methods useful in circulation research. Circ Res. 1980; 47(1):1-9. DOI: 10.1161/01.res.47.1.1. View

10.

Rodney W, Beaber R, Johnson R, Quan M . Physician compliance with colorectal cancer screening (1978-1983): the impact of flexible sigmoidoscopy. J Fam Pract. 1985; 20(3):265-9. View

11.

Donowitz L . Handwashing technique in a pediatric intensive care unit. Am J Dis Child. 1987; 141(6):683-5. DOI: 10.1001/archpedi.1987.04460060099044. View

12.

Freiman J, CHALMERS T, SMITH Jr H, Kuebler R . The importance of beta, the type II error and sample size in the design and interpretation of the randomized control trial. Survey of 71 "negative" trials. N Engl J Med. 1978; 299(13):690-4. DOI: 10.1056/NEJM197809282991304. View

13.

Pocock S, Hughes M, Lee R . Statistical problems in the reporting of clinical trials. A survey of three medical journals. N Engl J Med. 1987; 317(7):426-32. DOI: 10.1056/NEJM198708133170706. View

14.

Larsen K, Kirkwood C . Procedures performed by family physicians, internists, and a Medex in a small group practice. J Fam Pract. 1982; 15(2):285-92. View

15.

BRODY D, Lerman C, Wolfson H, Caputo G . Improvement in physicians' counseling of patients with mental health problems. Arch Intern Med. 1990; 150(5):993-8. View

16.

Sibley J, Sackett D, Neufeld V, Gerrard B, Rudnick K, Fraser W . A randomized trial of continuing medical education. N Engl J Med. 1982; 306(9):511-5. DOI: 10.1056/NEJM198203043060904. View

17.

Foote A, Erfurt J . Hypertension control at the work site. Comparison of screening and referral alone, referral and follow-up, and on-site treatment. N Engl J Med. 1983; 308(14):809-13. DOI: 10.1056/NEJM198304073081404. View

18.

Baxt W, Moody P . The impact of a physician as part of the aeromedical prehospital team in patients with blunt trauma. JAMA. 1987; 257(23):3246-50. View

19.

Martin D, Diehr P, Price K, Richardson W . Effect of a gatekeeper plan on health services use and charges: a randomized trial. Am J Public Health. 1989; 79(12):1628-32. PMC: 1349766. DOI: 10.2105/ajph.79.12.1628. View

20.

Wilson D, Taylor D, Gilbert J, Best J, Lindsay E, Willms D . A randomized trial of a family physician intervention for smoking cessation. JAMA. 1988; 260(11):1570-4. View