Scientists don't turn a blind eye to bias »

Many researchers are unaware that their expectations can introduce such strong bias, and so they don't feel the need to work blind. Scientific journals should insist on more robust experimental processes, say biologists after reviewing nearly 900,000 experiments. The team found that non-blind experiments - that is, where scientists knew which samples they were recording - averaged a 27 per cent stronger result than blind trials. However their review suggests that less than one in four experiments used blind data recording. "We found that non-blind papers tended to exaggerate differences between the experimental group and the control group," said lead researcher Dr Luke Holman, from the Research School of Biology at The Australian National University (ANU). "For example, a non-blind trial of a new drug might conclude that it is way more effective than a placebo, when in fact the drug's true effect is rather modest, simply because the researchers' expectations biased the results." The paper is published in PLOS biology at a time when experimental processes are under the microscope following increased levels of retractions and some journals are reviewing their peer review procedures. In the largest study of its kind, the team analysed nearly 900,000 papers from the PubMed life sciences database, using automated 'data mining'.