Talk:Randomized controlled trial

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What do we do about the inherent limitations? Recommendations?[edit]

Kudos on the limitations section, it is an accurate and concise enumeration of the consensus issues. Unfortunately, the sections on Randomization and Limitations are disjointed.

It is probably easier to focus on scientific limitations and not conflict of interest biases. To some extent, overcoming the limitations is about effective study design, which is probably too much to summarize here. Nonetheless, the authors of this page have hinted at suggestions with a very well written section on "Randomization".

But again, "Randomization" and "limitations" doesn't lead the reader to consider "ok now what do I do about it?" — Preceding unsigned comment added by 24.5.84.124 (talk) 03:29, 29 December 2012 (UTC)

Given our understanding of its limitations, isn't it time that we discourage references to RCT as a "gold standard?" It is a very fine tool, among many. It provides the best answer to a very specific question. But to get the right answer, we must ask the right question, and for many significant clinical (as well as social science) questions, RCT may not be the best tool at all. — Preceding unsigned comment added by 75.39.140.235 (talk) 14:59, 13 August 2013 (UTC)

Why[edit]

Why are there empty sub-headings? Guardian 00:15, 14 July 2006 (UTC)

control(led)[edit]

which to use in RCT, controlled vs control, is debatable. the number of google hits is 10x larger for the former so we should name it first as it is more widely accepted and understood. —The preceding unsigned comment was added by Mebden (talkcontribs) 10:16, 10 January 2007 (UTC).

The adjective controlled is grammatically correct. Tayste (edits) 22:44, 21 February 2010 (UTC)
Not so fast!
First, there are a number of inherent biases in what each particular search engine spits out (or claims to spit out). Not only that, but as Wikipedia is (perhaps unduly) influential in search engine hits, it can create a circular argument.
Second, a "control test" is readily recognised as a phrase in which the word "control" acts as an noun adjunct (what used to be known as an 'adjectival noun'). A "randomised control test" is also a grammatically correct rendition of a "control test" involving randomisation.
—DIV (137.111.13.4 (talk) 05:37, 4 March 2014 (UTC))

Duplication[edit]

Just noticed that the whole section under Urn randomisation is an exact copy of the section before.DanHertogs 15:22, 19 April 2007 (UTC)

It looks like it happened at this edit. I'll undo it. Good catch. Burlywood 18:42, 19 April 2007 (UTC)

Content inaccurate?[edit]

Challanging content: In intro paras -I dont believe randomisation ensures equal allocation - you can still have unequal allocation of confounding factors if you are unlucky. Others agree? (I have made no edits)

For any fixed covariate, the law of large numbers suggests that the method of random assignment has balance on that covariate, and large-deviation arguments suggest that the probability of great imbalance is very small. With lots of covariates (with complicated dependencies also), it is hard to say, but it is certainly plausible that randomization will fail to balance some covariates (say of 40 or more covariates, each of which some researcher may suspect of being confounding). In fact, there is substantial concern about covariate imbalance: See recent issues of Statistical Science, e.g. by Rosenberger or Paul Rosenbaum, etc.
I changed the introduction, to avoid the problem indicated by the previous editor (while still keeping the main message, that randomization is a good thing)! Kiefer.Wolfowitz (talk) 22:41, 27 June 2009 (UTC)

How random is random, and does it matter?[edit]

Should there be a section discussing HOW random the random allocations are? There are big statistical differences between sampling a stochastic process, using a pseudorandom number generator with adequate cycle length, and calling RAND() in Excel ... And what impact on Phase I, II or III trials might these differences have? Is it standard practice for study designers to describe randomization techniques? Daen (talk) 14:17, 19 November 2008 (UTC)

Clusters and correlation as a difficulty[edit]

This article should mention the difficulties associated with having to randomise clusters of individuals. An example is when a single intervention must be used for all subjects at a particular location for some reason of practicality, e.g. interventions are methods of care which are randomised to clinics or hospitals, therefore patients are clustered. I've just created cluster randomised controlled trial to delve into that topic more deeply, as time permits. Tayste (edits) 22:56, 21 February 2010 (UTC)

This is actually a challenging topic. I suggest referencing the "status quo" methods with a real world example for these complex topics (clusters and correlation). ANOVA is often used to ask such questions: "what is the measured variance within a group VS what is the measured variance between groups". Even with these groupwise statistical tests, the problem is at least as hard as figuring out a way to "measure" the similarity between a single patient sample observation and the "expected" observation. The more criteria we add, the more we run into multiple hypothesis problems Type-I errors. In a nutshell: even the simple problem is hard and becomes much harder when you consider the vast number of ways to "measure" the "distance" between two patient "samples".

Correlation is a very broad topic. Are you trying to correlate (and thereby cluster) patient samples, study features, or whole populations? I have had to review these issues as part of a informatics doctoral thesis. The more complex the method the less likely it is to be adopted in a RCT (or clinical practice).

http://web.psych.unimelb.edu.au/jkanglim/ANOVAandMANOVA.pdf http://en.wikipedia.org/wiki/Anova http://en.wikipedia.org/wiki/F-test http://en.wikipedia.org/wiki/Crossover_study

Sample size calculation[edit]

Should the article have a section on how to estimate the sample size that would be necessary in order to detect an effect of a given size? Or is that covered somewhere else in WP? Tayste (edits) 23:14, 21 February 2010 (UTC)

Opening paragraph[edit]

The brackets in the opening paragraph make the introduction to this article read really, really badly. I'm going to try make it a bit better. Tkenna (talk) 00:22, 6 May 2012 (UTC)

I've made a few further revisions to conserve some key epidemiological concepts, such as the experimental character of this study design. On a separate point, I feel many of the distinctions made in the last paragraph of the lead (ie "The terms "RCT" and randomized trial are often used synonymously, but some authors distinguish between "RCTs" which compare treatment groups with control groups not receiving treatment (as in a placebo-controlled study), and "randomized trials" which can compare multiple treatment groups with each other.[3] RCTs are sometimes known as randomized control trials.[4] RCTs are also called randomized clinical trials or randomized controlled clinical trials when they concern clinical research;[5][6][7]) are largely dated or WP:UNDUE (eg ref. 3). Consensus to reframe this paragraph and move some of the referenced material out of the lead? —MistyMorn (talk) 15:55, 6 May 2012 (UTC)
As I said on your talk page, I appreciate your edits on this article. I think it reads much better now while retaining the key points. AS far as reframing the paragraph goes, you'll have no opposition from me, you're clearly competent with these matters. Regards, Tkenna (talk) 16:24, 6 May 2012 (UTC)

This is one of the most important medical articles in Wikipedia. People can't understand medicine without understanding randomized, controlled trials. If people can't understand the introduction, they'll never get through the rest of the entry.

And yet this reads like an academic paper, written for people who already know what a randomized controlled trial is, written to show off how many polysyllabic medical terms the writer knows. It defines "randomized controlled trial" with the term "clinical trial." If a reader doesn't know what a randomized controlled trial is, they're not likely to know what a clinical trial is either. Before you use a term like "clinical trial," you have to explain what it is. In fact, most readers who don't know what a randomized controlled trial is won't know what a "scientific experiment" is either. This introduction has to be completely rewritten in plain English, preferably with one or more WP:RSs to support it. I would suggest seeing how professional writers, like New York Times reporters, have done it, rather than trying to create a definition out of your own head.

WP:NOTJOURNAL "Scientific journals and research papers. A Wikipedia article should not be presented on the assumption that the reader is well versed in the topic's field. Introductory language in the lead and initial sections of the article should be written in plain terms and concepts that can be understood by any literate reader of Wikipedia without any knowledge in the given field before advancing to more detailed explanations of the topic. While wikilinks should be provided for advanced terms and concepts in that field, articles should be written on the assumption that the reader will not or cannot follow these links, instead attempting to infer their meaning from the text." --Nbauman (talk) 06:31, 24 March 2014 (UTC)

Randomized clinical trials[edit]

RCT may also refer to randomized clinical trials. How we can incorporate this information? And which article wold be better to incorporate this information. Is this the good article to put this information? --Abhijeet Safai (talk) 06:12, 25 November 2012 (UTC)