Blind analysis: Hide results to seek the truth

Robert MacCoun & Saul Perlmutter

October 7, 2015

More fields should, like particle physics, adopt blind analysis to thwart bias, urge Robert MacCoun and Saul Perlmutter.

Decades ago, physicists including Richard Feynman noticed something worrying. New estimates of basic physical constants were often closer to published values than would be expected given standard errors of measurement1. They realized that researchers were more likely to 'confirm' past results than refute them — results that did not conform to their expectation were more often systematically discarded or revised.

To minimize this problem, teams of particle physicists and cosmologists developed methods of blind analysis: temporarily and judiciously removing data labels and altering data values to fight bias and error2. By the early 2000s, the technique had become widespread in areas of particle and nuclear physics. Since 2003, one of us (S.P.) has, with colleagues, been using blind analysis for measurements of supernovae that serve as a 'cosmic yardstick' in studies of the unexpected acceleration of the Universe's expansion3.

In several subfields of particle physics and cosmology, a new sort of analytical culture is forming: blind analysis is often considered the only way to trust many results. It is also being used in some clinical-trial protocols (the term 'triple-blinding' sometimes refers to this4), and is increasingly used in forensic laboratories as well.

But the concept is hardly known in the biological, psychological and social sciences. One of us (R.M.) has considerable experience conducting empirical research on legal and public-policy controversies in which concerns about bias are rampant (for example, drug legalization), but first encountered the concept when the two of us co-taught a transdisciplinary course at the University of California, Berkeley, on critical thinking and the role of science in democratic group decision-making. We came to recognize that the methods that physicists were using might improve trust and integrity in many sciences, including those with high-stakes analyses that are easily plagued by bias.

Read the full article:
Blind analysis: Hide results to seek the truth
October 7, 2015  |  Robert MacCoun and Saul Perlmutter   |   Nature

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Saul Perlmutter

Berkeley Center for Cosmological Physics, 2011 Nobel Laureate
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