The publication of research articles involving animal studies is central to many disciplines in science and biomedicine. Effective descriptions in such publications enable researchers to interpret the data, evaluate and replicate findings, and move the science forward.

To promote the inclusion of sufficient information in publications on animal studies,1 the National Research Council’s Institute for Laboratory Animal Research (ILAR) appointed a committee of experts in laboratory animal research and scientific publishing to provide guidance for journal editors, authors, and reviewers. Supported by private funding and other grants, the committee was charged as follows:

[To] prepare a short report aimed at editors of journals that publish animal studies. The report will outline the information that should be included in scientific papers regarding the animal studies to ensure that the study can be replicated. The extent of the needed information will be determined by the committee, but will include for example, conditions of housing and husbandry, genetic nomenclature, microbial status, detailed experimental manipulations and handling and use of pharmaceuticals. Evidence-based rationale for the need to include this information will be presented.

To complete its task, the committee conducted an extensive literature search about the impacts of various aspects of research animals and their environment. This report is the outcome of the committee’s work.

The committee believes that journal editors have a role to play in promoting the proper use of animals in research through the publication of adequate descriptions. The committee urges journal editors to actively promote effective and ethical research2 by encouraging the provision of sufficient information to enable assessment and interpretation of research findings and advancement of knowledge based on reproducible results.

This report provides journal editors, authors, and reviewers with guidance (and supporting references) for effective reporting of animal research in published articles based on adequate descriptions of

  • the research animal (section 3), with detailed information about the animals’

    age, sex, weight, and life stage (3.1),

    source (3.2),

    genetic nomenclature (3.3),

    microbial/pathogen status (3.4), and

    preparation and assignment (including control groups) (3.5);

  • the research animal environment (sections 4 and, for aquatic animals, 6), with detailed information about

    the micro- and macroenvironment (4.4 and 6.1),

    diet (4.1 and 6.2),

    water (4.2), and

    housing (4.3 and 6.3);

  • basic animal methodology, including aspects of animal care and use that can affect research outcomes (section 5), with detailed information about

    experimental effects (5.1),

    administration of substances (5.2),

    use of infectious agents (5.3),

    sample acquisition (5.4), and

    euthanasia (5.5).

The ability to interpret, evaluate, and reproduce biomedical and other types of laboratory animal research and testing is a reasonable minimum standard for the assessment of effective reporting in research articles. Journal editors can substantially contribute to the achievement of this standard through the articulation of clear policies and criteria for their authors and reviewers. This report complements existing checklists and resources by providing guidance and scientific evidence for the specific types of information that should be included in research publications to promote the advancement of science involving animal studies. It also describes approaches to facilitate the provision of such information.

1.1. The Need for Guidance

Analyses of published studies with research animals have demonstrated numerous deficiencies in the reporting of details in research methods for animal studies (Kilkenny 2009; Vesterinen et al. 2011). Despite multiple publications over the past 25 years calling attention to the critical factors and information necessary to enhance such reporting, most scientific journals provide relatively little specific guidance for authors and reviewers and there has been limited effort until quite recently (see next section) to address this systemic problem (Alfaro 2005; Ellery 1985; Öbrink and Rehbinder 2000; Smith et al. 1997). Most biomedical journal policies simply refer to regulatory requirements for animal use, without referring to critically important experimental design information.

Lack of sufficient experimental procedural detail about animal studies in the research literature has both scientific and ethical implications:

The articulation of clear guidelines by journals for the reporting of animal-related studies will help to address many of these concerns. Useful journal policies will define requirements for accurate descriptions of the research animal as an experimental test system, the critical elements of the research animal environment, and animal care and use practices that affect research results (Atlas 2003; Osborne et al. 2009).

1.2. Related Guidelines

In recent years there have been growing, but incomplete, efforts to enhance the reporting of animal-related research:

In addition to these resources, guidance is available in occasional articles about animal-related information to include in reporting (e.g., genetic and environmental description of important factors that can result in study variability). Such guidance is the result of interest in harmonizing standard operating procedures and methods to facilitate the comparison of animal studies across laboratories (Ayala et al. 2010) and to allow the sharing of animal phenotyping data, particularly for genetically modified mice (Gates et al. 2011; Mandillo et al. 2008; McGuinness et al. 2009; Würbel 2002).

Notwithstanding the examples cited above, there is no consensus or consistency among scientific publications about the basis for inclusion of adequate procedural detail in the reporting of animal research. The purpose of this report is to provide a firm basis for building such consistency. To the extent that a checklist approach is convenient, the committee cites as an example the ARRIVE Guidelines (Appendix A) and encourages journal editors and authors to use such a resource in conjunction with this report in determining the specific information to include in study reports for their publications.

1.3. Organization and Content of This Report

This report is organized in general sections that align with the types of information to be considered for inclusion in the materials and methods section of a scientific manuscript, with discussion of particular aspects and variables that can influence outcomes:

  • the research animal (including source, genetics, microbial/pathogen status, preparation and study assignment, and monitoring during the study);
  • the research animal environment (including diet, water, housing, and micro- and macroenvironment); and
  • basic animal methodology (including administration of anesthetics, analgesics, and other substances; tissue and fluid sampling; and euthanasia).

These sections present criteria to consider and the rationales behind them, together with supporting references that provide scientific evidence of the potential impacts discussed.

The committee acknowledges that this relatively concise guidance document cannot specifically address the array of animals and animal models used in biomedical research. Furthermore, because the vast majority are laboratory rodents,3 many of the references in this report pertain to these species, although they generally hold true for other animals used in research. In light of rapidly increasing research interest in zebrafish and other aquatic species, there is a separate section on aquatic systems.

Finally, in light of space limitations especially in print publications, the report presents possible methods to facilitate the provision of appropriate procedural details and data.



Including studies that use cells and tissues derived from animals for ex vivo and in vitro research.


The guiding principles for ethical animal research are the “three Rs”—reduction in the number of animals used, refinement of procedures to reduce animal stress and pain, and replacement of animals when possible (Russell and Burch 1959).


In 2007 it was estimated that 60% of National Institutes of Health extramural funding supported research using animals, and that more than 80% of this research involved the use of mice (Valli et al. 2007).