Help With CE research

Hello

I'm a conductor working in Canada and we are looking at collecting data about our groups on how their quality of life can change while attending CE.  We plan on using a QOL measure, specifically the SF-36 for our Adult groups and have yet to find a measure for the children groups.  We are feeling a bit lost with setting our methodology.  We want to know if we need to have a set group (specific number of people choosen) that we are looking at or if we can just start collecting data from our current participants and any new participants that start.  Anyone that could provide us some guidance with this would be appreciated.  Also any suggestions on a good QOL measure for children with motor disorders would be great.

Thanks

Rachel