Assessing quality
To be able to assess the quality of research, the standard of reporting of the methods and results is very important. Several authors have demonstrated deficiencies in the reporting of veterinary research studies, particularly clinical trials.
As a result, there have been calls for veterinary journals to adopt reporting guidelines to facilitate critical appraisal and increase the reliability and value of published research. Reporting guidelines are intended to improve the transparency, accuracy and completeness of reporting for different types of research.
However, clear and complete reporting is only one aspect of research quality. Good study design and execution of the study is also critical. When reading any scientific paper it is important to think about not only the study type but also how good the study is, then you can decide whether to believe the results or not. For example, randomised control trials are often seen as high quality evidence, but poor design and implementation can make them unreliable. Well-designed observational studies may provide stronger evidence than poorly designed and conducted trials.
Poor quality studies have a high risk of bias, which raises questions about the validity of the findings. Critical appraisal of every study (systematic reading of a study to understand key strengths and weaknesses) is therefore important to assess the risk of bias and the reliability of the results.
Tools for assessing quality fall into two types. Reporting guidelines are used by authors and journals when writing and publishing papers, to ensure that work is reported with sufficient transparency and clarity. Critical appraisal tools are useful when reading scientific studies, to help to determine whether the research is of good quality, and to enable comparison between different studies. There is some overlap in the questions asked in both of these types of assessment. Numerous tools for assessing study quality exist, including the checklists from CASP and the CEBM, as well as the AMSTAR tool for appraising systematic reviews.