Thank you Amy as always! The problem is to make sure these pre-testers never see the subjects train at the facility. So they have to be pretty much outlawed from the facility. Also, hard to know exactly their availability for the post- testing. If for some reason, they cannot make it for the post testing, then I will be in trouble. Hence my worry. My thinking is even if they did the training since they are not doing the post testing, the cannot in anyway influence the results right,. Here is a study in journal of gerontology - number one journal in gerontology. they used something similar. "Baseline physical assessments were conducted by the lead investigator (A.T.) or research assistant (S.O.) at the study site or participants’ home. After the 12-week intervention, all participants completed a follow-up postal questionnaire and the balance and mobility measures were reassessed by an assessor blind to group allocation (S.O.). " On Mon, Feb 16, 2015 at 6:37 PM, Dr Amy Price <[log in to unmask]> wrote: > Did you consider using same pre/post testers and separate trainers? > > Best > Amy > > > > On 2/16/15, 6:18 PM, "Anoop Balachandran" <[log in to unmask]> wrote: > > >Hi everyone, > > > >I had a question regarding blinding outcome assessors. > > > >Can I have different testers for testing people during pre test and post > >test? Or does it have to be the same people? > > > >I am planning to use the testers who did the pre-test to do the training > >too. And getting different testers for post-test who are blind to the > >group allocation or haven't seen the subjects train. > > > >Any thoughts please > > > >Thank you so much, > >Anoop >