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Critical Appraisal Resources for Nursing Research and EBP

What is a Randomized Controlled Trial?

A randomized controlled trial (RCT) is a type of quantitative, experimental research study.  RCTs involve "random assignment to groups and manipulation of the independent variable" (Schmidt & Brown, 2019, p. 172). 

RCTs investigate the effects of an intervention or treatment on study participants.  Participants are randomly assigned to either the intervention (treated) or control (untreated) group.  The purpose is to "look for differences between treated and untreated subjects" (Schmidt & Brown, 2019, p. 172). 

Level of Evidence: II

PRO TIPS: Randomized Controlled Trial Checklist

Each JBI Checklist provides tips and guidance on what to look for to answer each question.  These tips begin on page 4. 

Below are some additional Frequently Asked Questions about the Randomized Controlled Trial Checklist that have been asked by students in previous semesters. 

Frequently Asked Question: Response:

Question 1 asks whether there was true randomization.  My article mentions that participants were randomly assigned, but there is no additional detail provided.

Read carefully again the Methods section of your article.  Sometimes it is easy to miss certain details.  Occasionally, this information may be included toward the end of the article when the authors discuss any study limitations.  If they did not conduct true randomization, they may mention it as a limitation.  However, if you still cannot find this information, then it is advisable to answer Unclear for this question.  If the authors do not provide enough detail to make a definite Yes or No answer, then Unclear is the logical option.  
In Question 8, what is meant by "follow up"?

In randomized controlled trials, for follow-up to be complete, there must be complete knowledge about all participants for the duration of the trial including results of any measurements, observations, etc. However, it is not uncommon to lose participants in a study.  This happens when participants withdraw or drop-out, for example.  When this happens, follow-up is considered to be incomplete.  However, even if follow-up is incomplete, it is important for the researchers to describe reasons for this loss to follow-up (Tufanaru, Munn, Aromataris, Campbell, & Hopp, 2017).  See the explanatory notes for Question 8 in the JBI Checklist for further details. 

For Question 9, how can I tell whether all participants were analyzed in the groups to which they were randomized?  

Look for evidence in your article of a statistical strategy known as Intention-to-Treat Analysis or ITT Analysis (see the explanatory notes for Question 9 in the JBI Checklist for further details).  ITT analysis includes all study subjects in the groups to which they were randomly assigned, regardless of whether they withdrew from the study or ended up in another group to which they were not randomly assigned (Powers & Knapp, 2011). 

A full description of ITT analysis can be found in Powers & Knapp’s Dictionary of Nursing Theory and Research (2011) available as an e-book via the UToledo Libraries

References

Powers, B. & Knapp, T. (2011). Intent to treat (intention to treat). In Dictionary of Nursing Theory and Research (4th ed.). New York: Springer.

Tufanaru, C., Munn, Z., Aromataris, E., Campbell, J., & Hopp, L. (2017).  Chapter 3: Systematic reviews of effectiveness. In E. Aromataris & Z. Munn (Eds.), Joanna Briggs Institute reviewer's manual, The Joanna Briggs Institute. Retrieved from https://reviewersmanual.joannabriggs.org/ 

Articles on Randomized Controlled Trial Design and Methodology

Randomization, allocation concealment, and blinding

Bespalov, A., Wicke, K., & Castagné, V. (2020). Blinding and randomization. Handbook of Experimental Pharmacology, 257, 81-100. doi:10.1007/164_2019_279

Ferreira, J. C., & Patino, C. M. (2016). Randomization: Beyond tossing a coin. Jornal Brasileiro de Pneumologia, 42(5), 310. doi:10.1590/s1806-37562016000000296

Forder, P. M., Gebski, V. J., & Keech, A. C. (2005). Allocation concealment and blinding: When ignorance is bliss. Medical Journal of Australia, 182(2), 87-89.

Kabisch, M., Ruckes, C., Seibert-Grafe, M., & Blettner, M. (2011). Randomized controlled trials. Deutsches Ärzteblatt International, 108(39), 663-668. doi:10.3238/arztebl.2011.0663

Schulz, K. F., Chalmers, I., & Altman, D. G. (2002). The landscape and lexicon of blinding in randomized trials. Annals of Internal Medicine, 136(3), 254-259. doi:10.7326/0003-4819-136-3-200202050-00022

Intention-to-treat (ITT) analysis

McCoy, C. E. (2017). Understanding the intention-to-treat principle in randomized controlled trials. Western Journal of Emergency Medicine, 18(6), 1075-1078. doi:10.5811/westjem.2017.8.35985

Tufanaru, C. (2017). Demystifying intention-to-treat analyses. JBI Database of Systematic Review Implementation Reports, 15(4), 853-854. doi:10.11124/jbisrir-2017-003383