Generally single-blind means the patient is blind, but the doctor/treater is
not - see
http://en.wikipedia.org/wiki/Single_blind#Single-blind_trials
Double blind means that both are
I once had to analyse some data and it turned out the patient groups
variable was all mixed up. We christened this "triple blind" - even the
statistician does not know who is in which group! (In fact, it was noticing
some aberrant subgroups that first alerted us to this situation: the pharma
people did not know their data was screwy.)
JOHN BIBBY
On 16 April 2010 19:16, Dr Philip Sedgwick <[log in to unmask]> wrote:
> Dear Allstaters
>
> With respect to clinical trials, I was taught the definition of
> single-blind as the assessor was blind to allcoation but tthe patient was
> not. The concept I suppose was based on the fact it was always possible to
> blind the assessor to allcoation, but not necessarily the patient. Needless
> to say I have no reference. I was further taught, like most things with
> time, this definition has relaxed and it is possible for the assessor to be
> aware of allcoation, but the patient not - still resulting in single-blind
> trial.
>
> Does anyone have thoughts as to an original definition?
>
> Best wishes
>
> Philip Sedgwick
>
> St. George's, University of London
> London SW17 0RE
>
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