A code-break procedure is a set of rules which determine when planned
unblinding
In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...
should occur in a
blinded experiment
In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...
. FDA guidelines recommend that sponsors of blinded trials include a code-break procedure in their
standard operating procedure
A standard operating procedure (SOP) is a set of step-by-step instructions compiled by an organization to help workers carry out routine operations. SOPs aim to achieve efficiency, quality output, and uniformity of performance, while reducing misc ...
. A code-break procedure should only allow a participant to be unblinded before the conclusion of a trial in the event of an emergency. Code-break usually refers to the unmasking of treatment allocation, but can refer to any form of unblinding.
Traditionally, each patient's treatment allocation data was stored in a sealed envelopes, which was to be opened to break code. However, this system is prone to abuse. Reports of researchers opening envelopes prematurely or holding the envelopes up to lights to determine their contents has led some researchers to say that the use of sealed envelopes is no longer acceptable. , sealed envelopes were still in use in some clinical trials.
Modern clinical trials usually store this information in computer files.
See also
*
Sealedenvelope.com – a provider of code-break services
References
{{DEFAULTSORT:Code-break procedure
Design of experiments
Clinical research