Ten simple rules for reading randomized controlled trials

Authors

  • Alvaro Taype-Rondan Unidad de Investigación para la Generación y Síntesis de Evidencias en Salud, Vicerrectorado de Investigación, Universidad San Ignacio de Loyola, Lima, Peru; EviSalud – Evidencias en Salud, Lima, Peru. https://orcid.org/0000-0001-8758-0463
  • Sergio Goicochea-Lugo Unidad de Investigación para la Generación y Síntesis de Evidencias en Salud, Vicerrectorado de Investigación, Universidad San Ignacio de Loyola, Lima, Peru; EviSalud – Evidencias en Salud, Lima, Peru. https://orcid.org/0000-0002-0487-5547

DOI:

https://doi.org/10.21142/mecp.2026.1.2.e022

Keywords:

Randomized Controlled Trials as Topic, GRADE Approach, Evidence-based medicine, Bias, Decision Making

Abstract

Randomized controlled trials (RCTs) are central to evidence-based medicine, yet their interpretation can be challenging for clinicians without formal training in research methods. This article presents ten practical rules to guide the reading, interpretation, and application of RCTs, focusing on common pitfalls and key concepts. These include clarifying the study question using the PICO framework, distinguishing primary from secondary outcomes, understanding the purpose and limits of randomization, interpreting effect sizes and confidence intervals, and considering absolute as well as relative measures. The rules also emphasize systematic assessment of risk of bias, evaluation of external validity, and careful consideration of study limitations and their direction of bias. Finally, readers are encouraged to contextualize findings within the broader body of evidence before applying them to practice. Aimed at students and clinicians beginning to appraise biomedical evidence, these rules are intended as an accessible starting point to support more informed and critical interpretation of RCTs.

Downloads

Download data is not yet available.

References

1. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ. 1996;312(7023):71-72. doi: 10.1136/bmj.312.7023.71.

2. Schulz KF, Grimes DA. Generation of allocation sequences in randomised trials: chance, not choice. Lancet. 2002;359(9305):515-519. doi: 10.1016/S0140-6736(02)07683-3.

3. Sibbald B, Roland M. Understanding controlled trials: why are randomised controlled trials important? BMJ. 1998;316(7126):201. doi: 10.1136/bmj.316.7126.201.

4. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, AlonsoCoello P, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-926. doi: 10.1136/bmj.39489.470347.AD.

5. Greenhalgh T. How to read a paper: the basics of evidencebased medicine and healthcare. 6th ed. Hoboken: WileyBlackwell; 2019.

6. Schulz KF, Altman DG, Moher D; CONSORT Group. CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. BMJ. 2010;340:c332. doi: 10.1136/ bmj.c332.

7. Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page M, et al. eds. Cochrane Handbook for Systematic Reviews of Interventions [Internet]. Version 6.4. Cochrane; 2023 [cited 2026 Feb 2]. Available from: https://www.cochrane.org/ authors/handbooks-and-manuals/handbook/current

8. Critical Appraisal Skills Programme. CASP Randomised Controlled Trial Standard Checklist [Internet]. Oxford: CASP; 2020 [cited 2026 Feb 2]. Available from: https://casp-uk.net/

9. Richardson WS, Wilson MC, Nishikawa J, Hayward RS. The well-built clinical question: a key to evidence-based decisions. ACP J Club. 1995;123(3):A12-A13.

10. Chan AW, Tetzlaff JM, Gøtzsche PC, Altman DG, Mann H, Berlin JA, et al. SPIRIT 2013 explanation and elaboration: guidance for protocols of clinical trials. BMJ. 2013;346:e7586. doi: 10.1136/bmj.e7586.

11. Dwan K, Gamble C, Williamson PR, Kirkham JJ; Reporting Bias Group. Systematic review of the empirical evidence of study publication bias and outcome reporting bias. PLoS One. 2008;3(8):e3081. doi: 10.1371/journal.pone.0003081.

12. Schulz KF, Grimes DA. Allocation concealment in randomised trials: defending against deciphering. Lancet. 2002;359(9306):614-618. doi: 10.1016/S0140-6736(02)07750-4.

13. Lachin JM. Statistical considerations in the intent-to-treat principle. Control Clin Trials. 2000;21(3):167-189. doi: 10.1016/ s0197-2456(00)00046-5. Erratum in: Control Clin Trials 2000 Oct;21(5):526.

14. Wasserstein RL, Lazar NA. The ASA statement on p-values: context, process, and purpose. Am Stat. 2016;70(2):129-133. doi: 10.1080/00031305.2016.1154108.

15. Citrome L, Ketter TA. When does a difference make a difference? Interpretation of number needed to treat, number needed to harm, and likelihood to be helped or harmed. Int J Clin Pract. 2013;67(5):407-411. doi: 10.1111/ijcp.12142.

16. Higgins JP, Altman DG, Gøtzsche PC, Jüni P, Moher D, Oxman AD, et al. The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. BMJ. 2011;343:d5928. doi: 10.1136/bmj.d5928.

17. Sterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898. doi: 10.1136/bmj. l4898.

18. Rothwell PM. External validity of randomised controlled trials: ‘to whom do the results of this trial apply?’ Lancet. 2005;365(9453):82-93. doi: 10.1016/S0140-6736(04)17670-8.

19. Ioannidis JP. Why most published research findings are false. PLoS Med. 2005;2(8):e124. doi: 10.1371/journal.pmed.0020124.

20. Prasad V, Vandross A, Toomey C, Cheung M, Rho J, Quinn S, et al. A decade of reversal: an analysis of 146 contradicted medical practices. Mayo Clin Proc. 2013;88(8):790-798. doi: 10.1016/j.mayocp.2013.05.012.

21. Djulbegovic B, Guyatt GH. Progress in evidence-based medicine: a quarter century on. Lancet. 2017;390(10092):415- 423. doi: 10.1016/S0140-6736(16)31592-6.

Downloads

Published

2026-06-08

Issue

Section

Ten simple rules

How to Cite

1.
Taype-Rondan A, Goicochea-Lugo S. Ten simple rules for reading randomized controlled trials. Med Educ Clin Pract [Internet]. 2026 Jun. 8 [cited 2026 Jun. 29];1(2):e022. Available from: https://revistas.cientifica.edu.pe/index.php/mecp/article/view/3670