Statistician to the Stars!
I have been asked to write this review by a party who wishes to remain anonymous because of the fear of reprisal. See this article for background. Also this.
Dahn yoga might not be of interest to you, but this review is larger than that. It will show you how easy it is to publish material in a well known journal that is poor at best. Civilians are often shocked to discover that peer-review is only a weak indicator of correctness. This article removes some of that mystique.
This article is long, but has to be.
Study Abstract
Sung Lee, an internist, while at the Weill Cornell Medical School, conducted an experiment of Dahn yoga. He published the results in the paper: Prospective Study of New Participants in a Community-based Mind-body Training Program. It appeared in the Journal of General Internal Medicine, 2004 July; 19(7): 760–765.
This study has been touted by Dahn sympathizers: Ilchi Lee (Dahn founder) boasts of it (pdf), TV broadcasts (Sung Lee’s picture is in the upper-right corner), as supportive research, chiropractors in Sedona, and fan sites of Dahn.
Lee went to several locations in New York City and recruited people to join a three-month Dahn (introductory) program. All of these people self-selected themselves into the program; they came seeking yoga; all were new to Dahn. All were asked, at the beginning and end of the study, a series of questions.
The main ones were from the SF-36, a standard questionnaire. The most useful SF-36 “item” is question 1: “In general, would you say your health is: Excellent (5)…Poor (1)?”1 Another is, “Have you been a very nervous person? (6) – (1)” This “instrument” is divided into domains, such as “vitality” and “mental health,” which are simple functions of the questions. The “nervous” question is part of the mental health domain. Another is, “Have you felt downhearted and blue? (6) – (1)”
Papers which use the SF-36 rarely show the questions; they are content to report on the domains. Seeing the exact questions makes them sound far less impressive than when stated in their usual academese. For example, Lee calls the SF-36 “a validated health assessment instrument.”
Averages of the US population of each of the domains exist. The participants in the Dahn study began with scores lower than the US average: a fact which is not surprising, considering these were people who were newly arrived for exercise training.
There was no control group: all received the Dahn training. 194 started, and 171 completed the study. Three out of four were women. Five of the 171 reported an injury due to the training: it is unknown how many of the twenty-three who dropped out were injured.
From the abstract: “New participants in a community-based mind-body training program reported poor health-related quality of life at baseline and moderate improvements after 3 months of practice.” This means that several of the people had small increases in their three-month SF-36 scores.
That is, some people went from answering “A good bit of the time” to “A little of the time” on the question “Have you been a very nervous person?” And so on for some of the other questions.
From this, Lee was able to say that “Dahn worked.” Actually, the best that could be said was “Dahn didn’t cause too much harm.” Here’s why.
Specific objections
I was at Cornell at the time Lee was completing, presenting, and writing up his study. I made my objections known at that time. You must also understand that in academics “A paper is a paper”, and nearly anything can be published in some peer-reviewed journal somewhere. Because of this, the number of journals is staggering: they increase constantly.
