How Much of What You Know Just Ain't So?

About half...

Dinosaurs were cold-blooded. Increased K-12 spending and lower pupil/teacher ratios boost public school student outcomes. Most of the DNA in the human genome is junk. Saccharin causes cancer and a high fiber diet prevents it. Stars cannot be bigger than 150 solar masses.

In the past half-century, all of the foregoing facts have turned out to be wrong. In the modern world facts change all of the time, according to Samuel Arbesman, author of the new book The Half-Life of Facts: Why Everything We Know Has an Expiration Date...

Facts are being manufactured all of the time, and, as Arbesman shows, many of them turn out to be wrong. Checking each one is how the scientific process is supposed to work; experimental results need to be replicated by other researchers. So how many of the findings in 845,175 articles published in 2009 and recorded in PubMed, the free online medical database, were actually replicated? Not all that many. In 2011, a disquieting study in Nature reported that a team of researchers over 10 years was able to reproduce the results of only six out of 53 landmark papers in preclinical cancer research.