P.Mean >> Category >> Blinding in a research (created 2007-06-04).

Blinding is the process in a research study of hiding information about which treatment a patient receives. Also see Category: Placebos in research.


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Blind Prejudice - "Hard" scientists believe they are immune to bias. Robert Matthews. New Scientist 1998: (2117); 12. [Full text]. Description: This article makes the claim that parapsychology is far more rigorous than other scientific methods because their research papers use blinding far more often than other disciplines. It includes a quote from Rupert Sheldrake Most hard scientists take it for granted that blind techniques are unnecessary in their own field. Parapsychologists, on the other hand, have been constantly subjected to intense scrutiny by sceptics, and this has made them more rigorous." This claim is overly simplistic in my opinion, because blinding is just one of many dimensions of quality that need to be considered.

Mooney M, et al, The blind spot in the nicotine replacement therapy literature: Assessment of the doubleblind in clinical trials http://www.ncbi.nlm.nih.gov/pubmed/15135549 [PubMed abstract], Addict Behav., 2004 June;29(4):67

Creative Commons License All of the material above this paragraph is licensed under a Creative Commons Attribution 3.0 United States License. This page was written by Steve Simon and was last modified on 2010-04-11. The material below this paragraph links to my old website, StATS. Although I wrote all of the material listed below, my ex-employer, Children's Mercy Hospital, has claimed copyright ownership of this material. The brief excerpts shown here are included under the fair use provisions of U.S. Copyright laws.


3. Stats: Withholding information (November 28, 2005). A recent query on the IRB Forum asked about a pilot study. The goal of the pilot study was to see if different ways of presenting the materials would lead to an improvement in the response rate among participants. The researchers wanted to withhold information about the purpose of the pilot study from the participants because it might bias their response. The writer of the query was a member of the IRB that wanted some comments about whether it is okay to withhold this information and if patients should be told if they are participating in the pilot phase of the research.


2. Stats: Unblinding at the end of a study (November 1, 2004). When a study a placebo controlled study is completed, patients in both arms of the study are often offered the active drug at the end of the study at no cost as a way of thanking them for their participation. But some researchers want to continue to measure long term outcomes (outcomes that extend beyond the placebo phase of the study), so they will not reveal to the patients whether they received the active medication or placebo. This raises some difficult ethical issues. Here are a few references on this controversy that I saw on the IRBForum.

1. Stats: Breaking the blind (July 29, 2004). Someone asked an interesting question on the IRBForum today. Under what circumstances should the blinding for a trial be broken when an unexpected Serious Adverse Event (SAE) occurs?

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Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 United States License. This page was written by Steve Simon and was last modified on 2010-04-11.