Meta-Research: Why we need to report more than 'Data were Analyzed by t-tests or ANOVA'

Abstract

Transparent reporting is essential for the critical evaluation of studies. However, the reporting of statistical methods for studies in the biomedical sciences is often limited. This systematic review examines the quality of reporting for two statistical tests, t-tests and ANOVA, for papers published in a selection of physiology journals in June 2017. Of the 328 original research articles examined, 277 (84.5%) included an ANOVA or t-test or both. However, papers in our sample were routinely missing essential information about both types of tests: for example, 213 papers (95% of the papers that used ANOVA) did not contain the information needed to determine what type of ANOVA was performed, and 26.7% of papers did not specify what post-hoc test was performed. Most papers also omitted the information needed to verify ANOVA results. Essential information about t-tests was also missing in many papers. We conclude by discussing measures that could be taken to improve the quality of reporting.

Data availability

All data from the systematic review has been uploaded with the manuscript, along with the abstraction protocol.

Article and author information

Author details

  1. Tracey L Weissgerber

    Division of Nephrology and Hypertension, Mayo Clinic, Rochester, United States
    For correspondence
    weissgerber.tracey@mayo.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7490-2600
  2. Oscar Alejandro Garcia Valencia

    Division of Nephrology and Hypertension, Mayo Clinic, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0186-9448
  3. Vesna D Garovic

    Division of Nephrology and Hypertension, Mayo Clinic, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Natasa M Milic

    Division of Nephrology and Hypertension, Mayo Clinic, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Stacey J Winham

    Division of Nephrology and Hypertension, Mayo Clinic, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.

Funding

American Heart Association (16GRNT30950002)

  • Tracey L Weissgerber

National Center for Advancing Translational Sciences (UL1 TR000135)

  • Tracey L Weissgerber

Mayo Clinic (Robert W. Fulk Career Development Award)

  • Tracey L Weissgerber

National Cancer Institute (R03-CA212127)

  • Stacey J Winham

Walter and Evelyn Simmers Career Development Award for Ovarian Cancer Research

  • Stacey J Winham

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

© 2018, Weissgerber et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Tracey L Weissgerber
  2. Oscar Alejandro Garcia Valencia
  3. Vesna D Garovic
  4. Natasa M Milic
  5. Stacey J Winham
(2018)
Meta-Research: Why we need to report more than 'Data were Analyzed by t-tests or ANOVA'
eLife 7:e36163.
https://doi.org/10.7554/eLife.36163
  1. Further reading

Further reading

    1. Immunology and Inflammation
    2. Medicine
    Haiyi Fei, Xiaowen Lu ... Lingling Jiang
    Research Article

    Preeclampsia (PE), a major cause of maternal and perinatal mortality with highly heterogeneous causes and symptoms, is usually complicated by gestational diabetes mellitus (GDM). However, a comprehensive understanding of the immune microenvironment in the placenta of PE and the differences between PE and GDM is still lacking. In this study, cytometry by time of flight indicated that the frequencies of memory-like Th17 cells (CD45RACCR7+IL-17A+CD4+), memory-like CD8+ T cells (CD38+CXCR3CCR7+HeliosCD127CD8+) and pro-inflam Macs (CD206CD163CD38midCD107alowCD86midHLA-DRmidCD14+) were increased, while the frequencies of anti-inflam Macs (CD206+CD163CD86midCD33+HLA-DR+CD14+) and granulocyte myeloid-derived suppressor cells (gMDSCs, CD11b+CD15hiHLA-DRlow) were decreased in the placenta of PE compared with that of normal pregnancy (NP), but not in that of GDM or GDM&PE. The pro-inflam Macs were positively correlated with memory-like Th17 cells and memory-like CD8+ T cells but negatively correlated with gMDSCs. Single-cell RNA sequencing revealed that transferring the F4/80+CD206 pro-inflam Macs with a Folr2+Ccl7+Ccl8+C1qa+C1qb+C1qc+ phenotype from the uterus of PE mice to normal pregnant mice induced the production of memory-like IL-17a+Rora+Il1r1+TNF+Cxcr6+S100a4+CD44+ Th17 cells via IGF1–IGF1R, which contributed to the development and recurrence of PE. Pro-inflam Macs also induced the production of memory-like CD8+ T cells but inhibited the production of Ly6g+S100a8+S100a9+Retnlg+Wfdc21+ gMDSCs at the maternal–fetal interface, leading to PE-like symptoms in mice. In conclusion, this study revealed the PE-specific immune cell network, which was regulated by pro-inflam Macs, providing new ideas about the pathogenesis of PE.

    1. Medicine
    Gabriel O Heckerman, Eileen Tzng ... Adrienne Mueller
    Research Article

    Background: Several fields have described low reproducibility of scientific research and poor accessibility in research reporting practices. Although previous reports have investigated accessible reporting practices that lead to reproducible research in other fields, to date, no study has explored the extent of accessible and reproducible research practices in cardiovascular science literature.

    Methods: To study accessibility and reproducibility in cardiovascular research reporting, we screened 639 randomly selected articles published in 2019 in three top cardiovascular science publications: Circulation, the European Heart Journal, and the Journal of the American College of Cardiology (JACC). Of those 639 articles, 393 were empirical research articles. We screened each paper for accessible and reproducible research practices using a set of accessibility criteria including protocol, materials, data, and analysis script availability, as well as accessibility of the publication itself. We also quantified the consistency of open research practices within and across cardiovascular study types and journal formats.

    Results: We identified that fewer than 2% of cardiovascular research publications provide sufficient resources (materials, methods, data, and analysis scripts) to fully reproduce their studies. Of the 639 articles screened, 393 were empirical research studies for which reproducibility could be assessed using our protocol, as opposed to commentaries or reviews. After calculating an accessibility score as a measure of the extent to which an article makes its resources available, we also showed that the level of accessibility varies across study types with a score of 0.08 for Case Studies or Case Series and 0.39 for Clinical Trials (p = 5.500E-5) and across journals (0.19 through 0.34, p = 1.230E-2). We further showed that there are significant differences in which study types share which resources.

    Conclusion: Although the degree to which reproducible reporting practices are present in publications varies significantly across journals and study types, current cardiovascular science reports frequently do not provide sufficient materials, protocols, data, or analysis information to reproduce a study. In the future, having higher standards of accessibility mandated by either journals or funding bodies will help increase the reproducibility of cardiovascular research.

    Funding: Authors Gabriel Heckerman, Arely Campos-Melendez, and Chisomaga Ekwueme were supported by an NIH R25 grant from the National Heart, Lung and Blood Institute (R25HL147666). Eileen Tzng was supported by an AHA Institutional Training Award fellowship (18UFEL33960207).