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. 2019 Oct:114:125-132.
doi: 10.1016/j.jclinepi.2019.06.011. Epub 2019 Jun 20.

Who is in this study, anyway? Guidelines for a useful Table 1

Eleanor Hayes-Larson  1 , Katrina L Kezios  2 , Stephen J Mooney  3 , Gina Lovasi  4
Affiliations

Who is in this study, anyway? Guidelines for a useful Table 1

Eleanor Hayes-Larson et al. J Clin Epidemiol. 2019 Oct.

Abstract

Objective: Epidemiologic and clinical research papers often describe the study sample in the first table. If well-executed, this "Table 1" can illuminate potential threats to internal and external validity. However, little guidance exists on best practices for designing a Table 1, especially for complex study designs and analyses. We aimed to summarize and extend the literature related to reporting descriptive statistics.

Study design and setting: In consultation with existing guidelines, we synthesized and developed reporting recommendations driven by study design and focused on transparency related to potential threats to internal and external validity.

Results: We describe a basic structure for Table 1 and discuss simple modifications in terms of columns, rows, and cells to enhance a reader's ability to judge both internal and external validity. We further highlight several analytic complexities common in epidemiologic research (missing data, sample weights, clustered data, and interaction) and describe possible variations to Table 1 to maintain and add clarity about study validity in light of these issues. We discuss considerations and tradeoffs in Table 1 related to breadth and comprehensiveness vs. parsimony and reader-friendliness.

Conclusion: We anticipate that our work will guide authors considering layouts for Table 1, with attention to the reader's perspective.

Keywords: Clinical research; Descriptive statistics; Epidemiologic methods; External validity; Generalizability; Internal validity; Tables.

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Conflict of interest statement

Declarations of interest: none

Figures

Figure 1.
Figure 1.
Basic Table 1 structure and analysis-specific considerations affecting columns, rows, and cells.
Figure 2.
Figure 2.
Example construction of Table 1 for a hypothetical case-control study.
Figure 3.
Figure 3.
Example construction of Table 1 for a hypothetical cohort study with missing data.
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Comment in

References

    1. Moher D, Hopewell S, Schulz KF, Montori V, Gotzsche PC, Devereaux PJ, et al. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. Int J Surg. 2012;10(1):28–55. - PubMed
    1. Vandenbroucke JP, von Elm E, Altman DG, Gotzsche PC, Mulrow CD, Pocock SJ, et al. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): explanation and elaboration. Int J Surg. December 2014;12(12):1500–1524. - PubMed
    1. Schwartz S, Campbell UB, Gatto NM, Gordon K. Toward a clarification of the taxonomy of “bias” in epidemiology textbooks. Epidemiology. March 2015;26(2):216–222. - PubMed
    1. Malmivaara A Generalizability of findings from randomized controlled trials is limited in the leading general medical journals. J Clin Epi. 2019;107:36–41. - PubMed
    1. von Elm E, Altman DG, Egger M, Pocock SJ, Gotzsche PC, Vandenbroucke JP, et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies. Int J Surg. December 2014;12(12):1495–1499. - PubMed

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