Issues in Randomization Outline

Simple Important Steps to Avoid Problems• Check eligibility criteria thoroughly prior toenrollment– Unnecessary drop out if realize afterrandomization subject not eligible andforced to withdraw– No matter how quickly a subject iswithdrawn all randomized subjects includedin ITT• Avoid a delay between randomization andtreatment initiation– Delays can lead to unnecessary missingdata that affects ITT64Documentation• Protocol should specify who maintains/hasaccess to unblinded treatment assignment– Protocol should also specify criteria forunmasking and treatment of earlywithdrawals• There should be documentation of therandomization algorithm, randomization list,and how it was implemented– Reproducibility is key65Possible Implementations of BlindedRandomization• Sequenced sealed envelopes– Prone to tampering!• Sequenced bottles/packets– Generally carried out by pharmacy/drugcompany• Phone call to central location– Live response, IVRS (Voice ResponseSystem)• On site computer system• Web based• Best plans easily messed up in implementation22