Addressing the unit of analysis in medical care studies: A systematic review

Aaron W. Calhoun; Gordon H. Guyatt; Michael D. Cabana; Downing Lu; David A. Turner; Stacey Valentine; Adrienne G. Randolph

doi:10.1097/MLR.0b013e3181649412

Addressing the unit of analysis in medical care studies: A systematic review

Aaron W. Calhoun, Gordon H. Guyatt, Michael D. Cabana, Downing Lu, David A. Turner, Stacey Valentine, Adrienne G. Randolph

Research output: Contribution to journal › Review article › peer-review

14 Scopus citations

Abstract

OBJECTIVE: We assessed the frequency that patients are incorrectly used as the unit of analysis among studies of physicians' patient care behavior in articles published in high impact journals. METHODS: We surveyed 30 high-impact journals across 6 medical fields for articles susceptible to unit of analysis errors published from 1994 to 2005. Three reviewers independently abstracted articles using previously published criteria to determine the presence of analytic errors. RESULTS: One hundred fourteen susceptible articles were found published in 15 journals, 4 journals published the majority (71 of 114 or 62.3%) of studies, 40 were intervention studies, and 74 were noninterventional studies. The unit of analysis error was present in 19 (48%) of the intervention studies and 31 (42%) of the noninterventional studies (overall error rate 44%). The frequency of the error decreased between 1994-1999 (N = 38; 65% error) and 2000-2005 (N = 76; 33% error) (P = 0.001). CONCLUSIONS: Although the frequency of the error in published studies is decreasing, further improvement remains desirable.

Original language	English (US)
Pages (from-to)	635-643
Number of pages	9
Journal	Medical Care
Volume	46
Issue number	6
DOIs	https://doi.org/10.1097/MLR.0b013e3181649412
State	Published - Jun 2008
Externally published	Yes

Keywords

Cluster analysis
Interpretation of clinical trials
Statistical bias
Study design
Unit of analysis error

ASJC Scopus subject areas

Public Health, Environmental and Occupational Health

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1097/MLR.0b013e3181649412

Cite this

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title = "Addressing the unit of analysis in medical care studies: A systematic review",

abstract = "OBJECTIVE: We assessed the frequency that patients are incorrectly used as the unit of analysis among studies of physicians' patient care behavior in articles published in high impact journals. METHODS: We surveyed 30 high-impact journals across 6 medical fields for articles susceptible to unit of analysis errors published from 1994 to 2005. Three reviewers independently abstracted articles using previously published criteria to determine the presence of analytic errors. RESULTS: One hundred fourteen susceptible articles were found published in 15 journals, 4 journals published the majority (71 of 114 or 62.3%) of studies, 40 were intervention studies, and 74 were noninterventional studies. The unit of analysis error was present in 19 (48%) of the intervention studies and 31 (42%) of the noninterventional studies (overall error rate 44%). The frequency of the error decreased between 1994-1999 (N = 38; 65% error) and 2000-2005 (N = 76; 33% error) (P = 0.001). CONCLUSIONS: Although the frequency of the error in published studies is decreasing, further improvement remains desirable.",

keywords = "Cluster analysis, Interpretation of clinical trials, Statistical bias, Study design, Unit of analysis error",

author = "Calhoun, {Aaron W.} and Guyatt, {Gordon H.} and Cabana, {Michael D.} and Downing Lu and Turner, {David A.} and Stacey Valentine and Randolph, {Adrienne G.}",

year = "2008",

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T1 - Addressing the unit of analysis in medical care studies

T2 - A systematic review

AU - Calhoun, Aaron W.

AU - Guyatt, Gordon H.

AU - Cabana, Michael D.

AU - Lu, Downing

AU - Turner, David A.

AU - Valentine, Stacey

AU - Randolph, Adrienne G.

PY - 2008/6

Y1 - 2008/6

N2 - OBJECTIVE: We assessed the frequency that patients are incorrectly used as the unit of analysis among studies of physicians' patient care behavior in articles published in high impact journals. METHODS: We surveyed 30 high-impact journals across 6 medical fields for articles susceptible to unit of analysis errors published from 1994 to 2005. Three reviewers independently abstracted articles using previously published criteria to determine the presence of analytic errors. RESULTS: One hundred fourteen susceptible articles were found published in 15 journals, 4 journals published the majority (71 of 114 or 62.3%) of studies, 40 were intervention studies, and 74 were noninterventional studies. The unit of analysis error was present in 19 (48%) of the intervention studies and 31 (42%) of the noninterventional studies (overall error rate 44%). The frequency of the error decreased between 1994-1999 (N = 38; 65% error) and 2000-2005 (N = 76; 33% error) (P = 0.001). CONCLUSIONS: Although the frequency of the error in published studies is decreasing, further improvement remains desirable.

AB - OBJECTIVE: We assessed the frequency that patients are incorrectly used as the unit of analysis among studies of physicians' patient care behavior in articles published in high impact journals. METHODS: We surveyed 30 high-impact journals across 6 medical fields for articles susceptible to unit of analysis errors published from 1994 to 2005. Three reviewers independently abstracted articles using previously published criteria to determine the presence of analytic errors. RESULTS: One hundred fourteen susceptible articles were found published in 15 journals, 4 journals published the majority (71 of 114 or 62.3%) of studies, 40 were intervention studies, and 74 were noninterventional studies. The unit of analysis error was present in 19 (48%) of the intervention studies and 31 (42%) of the noninterventional studies (overall error rate 44%). The frequency of the error decreased between 1994-1999 (N = 38; 65% error) and 2000-2005 (N = 76; 33% error) (P = 0.001). CONCLUSIONS: Although the frequency of the error in published studies is decreasing, further improvement remains desirable.

KW - Cluster analysis

KW - Interpretation of clinical trials

KW - Statistical bias

KW - Study design

KW - Unit of analysis error

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JO - Medical Care

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Addressing the unit of analysis in medical care studies: A systematic review

Abstract

Keywords

ASJC Scopus subject areas

UN SDGs

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