This disturbing report in the New Yorker may expain the reason:
Read more http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer#ixzz1882gDP9D
Before the effectiveness of a drug can be confirmed, it must be tested again and again. The test of replicability, as it’s known, is the foundation of modern research. It’s a safeguard for the creep of subjectivity. But now all sorts of well-established, multiply confirmed findings have started to look increasingly uncertain. It’s as if our facts are losing their truth...
The disturbing implication of this study is that a lot of extraordinary scientific data is nothing but noise. This suggests that the decline effect is actually a decline of illusion. Many scientific theories continue to be considered true even after failing numerous experimental tests. The decline effect is troubling because it reminds us how difficult it is to prove anything.
Read more http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer#ixzz1882gDP9D
