Introduction
Welcome to NERDCAT: A Clinician’s Guide to Appraising Randomized Controlled Trials and Systematic Reviews/Meta-Analyses. Led by Dr. Ricky Turgeon, NERDCAT was designed to help clinicians make sense of clinical research and has two core components: (1) The NERDCAT appraisal checklists, which facilitate the systematic appraisal of clinical studies; and (2) detailed guidance on how to address the NERDCAT appraisal checklist questions, along with rationales, supporting empiric evidence where available, and examples. While tools like CONSORT and PRISMA are aimed at researchers to facilitate adequate reporting of key details of their randomized controlled trials and systematic reviews, NERDCAT appraisal checklists are written “for clinicians, by clinicians” explicitly for the purpose of appraising clinical evidence and applying it to practice.
NERDCAT is organized into 3 chapters (Generalizability, Randomized Controlled Trials (RCTs), and Systematic Reviews and Meta-Analyses), an appendix of core statistical concepts (Appendix: Fundamental Statistics), and a comprehensive glossary of key terms. The Generalizability chapter is applicable to any clinical study type, including RCTs and systematic reviews/meta-analyses. NERDCAT can be read front-to-back or perused as a reference guide when appraising a study. Since the appendix describes the foundational statistical concepts necessary to understand the rest of the book, it is likely the best starting point for those unsure where to begin.
NERDCAT is structured around a core framework for appraising clinical studies adapted from the Users’ Guides to the Medical Literature (Guyatt G et al.), which centers around 3 key questions:
- Generalizability: Who was studied and how do these results apply to my patients?
- Internal validity: How serious is the risk of bias and how might it impact the results?
- What are the results?: What are the estimates of benefits & harms, how precise are those estimates, and are observed differences clinically important?
The NERDCAT checklists are available at the following Google Doc links:
Randomized controlled trials are those in which participants are randomly allocated to two or more groups which are given different treatments.
A review that systematically identifies all potentially relevant studies on a research question. The aggregate of studies is then evaluated with respect to factors such as risk of bias of individual studies or heterogeneity among results. The qualitative combination of results is a systematic review.
A meta-analysis is a quantitative combination of the data obtained in a systematic review.
Refers to the extent to which the trial results are applicable beyond the patients included in the study. Also known as external validity.
Systematic deviation of an estimate from the truth (either an overestimation or underestimation) caused by a study design or conduct feature. See the Catalog of Bias for specific biases, explanations, and examples.
