Take all scientific studies, especially those featured in the mainstream media, with multiple grains of salt. From Ivan Couronne at yahoo.com:
A skull made of sugar — one of a large number of foodstuffs that have been associated with cancer risks or benefits, despite a lack of strong direct evidence
Washington (AFP) – A few years ago, two researchers took the 50 most-used ingredients in a cook book and studied how many had been linked with a cancer risk or benefit, based on a variety of studies published in scientific journals.
The result? Forty out of 50, including salt, flour, parsley and sugar. “Is everything we eat associated with cancer?” the researchers wondered in a 2013 article based on their findings.
Their investigation touched on a known but persistent problem in the research world: too few studies have large enough samples to support generalized conclusions.
But pressure on researchers, competition between journals and the media’s insatiable appetite for new studies announcing revolutionary breakthroughs has meant such articles continue to be published.
“The majority of papers that get published, even in serious journals, are pretty sloppy,” said John Ioannidis, professor of medicine at Stanford University, who specializes in the study of scientific studies.
This sworn enemy of bad research published a widely cited article in 2005 entitled: “Why Most Published Research Findings Are False.”
Since then, he says, only limited progress has been made.
Some journals now insist that authors pre-register their research protocol and supply their raw data, which makes it harder for researchers to manipulate findings in order to reach a certain conclusion. It also allows other to verify or replicate their studies.
Because when studies are replicated, they rarely come up with the same results. Only a third of the 100 studies published in three top psychology journals could be successfully replicated in a large 2015 test.
Medicine, epidemiology, population science and nutritional studies fare no better, Ioannidis said, when attempts are made to replicate them.
“Across biomedical science and beyond, scientists do not get trained sufficiently on statistics and on methodology,” Ioannidis said.
Too many studies are based solely on a few individuals, making it difficult to draw wider conclusions because the samplings have so little hope of being representative.
To continue reading: Beware those scientific studies — most are wrong, researcher warns