Posted on 06/16/2005 12:15:08 AM PDT by neverdem
Challenging earlier findings, two studies from the Heritage Foundation reported yesterday that young people who took virginity pledges had lower rates of acquiring sexually transmitted diseases and engaged in fewer risky sexual behaviors.
The new findings were based on the same national survey used by earlier studies and conducted by the Department of Health and Human Services. But the authors of the new study used different methods of statistical analysis from those in an earlier one that was widely publicized, making direct comparisons difficult.
Independent experts called the new findings provocative, but criticized the Heritage team's analysis as flawed and lacking the statistical evidence to back its conclusions. The new findings have not been submitted to a journal for publication, an author said. The independent experts who reviewed the study said the findings were unlikely to be published in their present form.
The authors of the new studies, Dr. Robert Rector, a senior research fellow in policy studies at the foundation, and Dr. Kirk A. Johnson, a senior policy analyst there, said their findings contradicted those published in March in The Journal of Adolescent Health by Dr. Peter Bearman, the chairman of the sociology department at Columbia University, and Hannah Brückner of Yale University. The earlier study found that a majority of teenagers who took the pledge did not live up to their promises and developed sexually transmitted diseases about the same rate as adolescents who had not made such pledges. It also found that the promise did tend to delay the start of intercourse by 18 months.
(Excerpt) Read more at nytimes.com ...
By including Chlamydia the sociologist may be correct about the prevalence of all STD infections, but even Chlamydia has an eventual sign or symptom in females having no children or complaining about infertility, i.e, a sign or a symptom, respectively. While they may initially be asymptomatic, almost all STDs have other signs or symptoms that get worse with time.
He said in an interview that it was "a glaring error" to use the result of a statistical test at a 0.10 level of significance when journals generally use a lower and more rigorous level of 0.05.
That means that the statistical association, i.e. probability or P, was likely to happen by chance less or equal to than 1 out 10 times using a probability of less than or equal to 0.10, versus less than or equal to 1 out of 20 times with a P less than or equal to 0.05.
Could that be translated into simple layman's laguage, please?
Does it mean taking the pledge for chastity works, or not?
The pledge is much easier when nobody is chasing you that way.
Being chaste beats being chased.
( ..couldn't resist.. :-)
I suppose.
My point was they surely did not attempt to determine who is attractive and who is not. (Believe it or not, men consider this aspect when selecting which ladies they want to seduce, thus making this study pointless.)
Well, I've seen really fugly folks with kids in tow, so I'm not convinced your point is valid.
Yep. Some of us uglies (me) do things from low self-esteem!
Either way, I'm sure they can't consider all these factors.
Statistics is basically an exercise in probability. It is something like the arguments about correlation versus causation. There's a stronger statistical correlation when P equals or is less than 0.05 versus P equals or is less than 0.10 by a factor of at least 2. The usual scientific convention is to use P equals or is less than 0.05, i.e. picking random samples you would expect an erroneous result less than one out 20 samples. Any corrections will be appreciated.
Obesity, Smoking Speed Aging Process
FReepmail me if you want on or off my health and science ping list. Every puff and added pound makes cells old before their time, study finds
MONDAY, June 13 (HealthDay News) -- Researchers are providing one more reason to drop excess weight and quit smoking: a new study finds that both accelerate human aging.
The new study included more than 1,100 British women between 18 and 76 years of age. The women filled out a questionnaire on their smoking history and provided blood samples, which were also tested for concentrations of a body fat regulator called leptin and for telomere length.
Telomeres cap the ends of chromosomes in cells and protect them from damage. However, each time a cell divides -- and as people age -- these caps get shorter, so decreases in telomere length have long been associated with the aging process.
Reporting June 14 in the early online edition of The Lancet, the British researchers found that telomeres of obese women and smokers were much shorter than those of lean women and those who'd never smoked. In contrast, lean women had much longer telomeres than moderately overweight women who, in turn, had longer telomeres than obese women.
Each pack-year (the number of cigarettes smoked per day times the number of years of smoking) smoked was equivalent to an 18 percent telomere shortening, in addition to normal telomere shrinkage, the study found.
Overall, obese women aged an additional 8.8 years -- based on telomere length -- compared to lean women, the researchers reported. A current or previous history of smoking entailed an average 4.6 year increase in aging compared to never-smokers, while those with long-term smoking habits -- a pack-a-day for 40 years -- added an additional 7.4 years of aging to their life compared to those who stayed away from cigarettes completely, the study found.
"Our results emphasize the potential wide-ranging effects of the two most important preventable exposures in developed countries -- cigarettes and obesity," researcher Tim Spector of St. Thomas' Hospital, U.K., said in a prepared statement.
More information
The Alliance for Aging Research has more about aging.
SOURCE: The Lancet, news release, June 14, 2005
FReepmail me if you want on or off my health and science ping list.
Correction!!
Apologies to Dr. Bearman. On reading the actual NY Times article, it was David Landry, a senior research associate at the Alan Guttmacher Institute in New York, who made the statement about the p < .10 being inappropriate.
For those of you unfamiliar with the Institute:
"The Institute's mission is to protect the reproductive choices of all women and men in the United States and throughout the world. It is to support their ability to obtain the information and services needed to achieve their full human rights, safeguard their health and exercise their individual responsibilities in regard to sexual behavior and relationships, reproduction and family formation." http://www.agi-usa.org/about/
Now that's what I call going to a disinterested 3rd party for an objective assessment of statistical methodology!! Another example of great journalism from the Times.
In simple layman's language, loosening from 0.05 significance to 0.10 significance to get the result you want is known as "junk science".
When a (classical) statistical judgment is made (for example, A > B), a confidence interval is supposed to be given also. It is a measure of "how confident" one is in the result. (I won't go into the philosophy.) The primary factor in determining confidence intervals is the number of samples; more samples generally mean more confidence.
A confidence interval of 5% basically means that, "Were many randomly chosen samples measured, 5% would have worse results than those of the actual sample." The 5% is arbitrary; it stems from the early 1900s when computation of confidence intervals was done with pencil and paper (or chalk and slate). Tables were published at the 5% level and this became the norm.
The criticism of the published result is that it used a 10% confidence level. This means that the results are more "uncertain" or that the conclusion is "weaker" than normal.
There is some criticism that the observations have systematic (rather than sampling) errors. I haven't read the original work, so I don't know about the results. I just like to criticize methodology.
10%-significance levels are commonly reported in social-science journals.
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