Bad Science Part 2: Blinding

26 Nov

Continuing my ‘homage’ to Ben Goldacre’s excellent new book ‘Bad Science‘, this time we discuss Ben’s explanation of the scientific concept of Blinding.

One important feature of a good trial is that neither the experimenters nor the patients know if they got the [thing we want to test] or the simple placebo sugar pill, because we want to be sure that any difference we measure is the result of the difference between the pills and not of people expectations or biases.

Page 45. Inserts mine.

The stakes are fairly important. Ben tells how the biggest figures in evidence based medicine got together and did a review of blinding in all kinds of trials of medial drugs. The trials that used bad blinding techniques (or none at I guess) exaggerated the benefits of treatments by 17%.

Frequently I hear complaints from people who don’t care for the scientific method or who believe it is part of a massive conspiracy to cover up ‘the truth’ that things like blinding, randomisation, placebo effects, using controls and meta-analysis are essentially silly nitpicking to rubbish ‘the truth’. Clearly, when there is a 17% exaggeration, this cannot be accurate.

When doctors and scientists say that a study was methodologically flawed and unreliable, it’s not because they’re being mean, or trying to maintain the ‘hegemony’ or to keep the backhanders coming from the pharmaceutical industry: it’s because the study was poorly performed – it costs nothing to blind properly – and simply wasn’t a fair test.

Page 47.

Read more about Blinding techniques at Wikipedia.

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