Pre-testing two competing surveys with overlapping items

Hi all

I hope this is the correct forum – if you have a suggestion for a more suitable forum please let me know.

I have started work in a new organisation where my team have developed two surveys and are up to pre-testing. The two versions mostly share the same items, except for 3-4 different items on each. The aim of the pre-test is twofold; 1. pre-test the items in both (despite the overlap in items) 2. decide which survey is the ‘better’ (still trying to work this out) and will progress to survey production. My experience in pre-testing is limited to testing items in one survey, so I am wondering if anyone has experience in testing two surveys, or can point me in the direction of a suitable reference? My hunch is to include all items in one survey and reduce the discordant items… but maybe there is a better way.

Any advise would be greatly appreciated.

Thanks in advance for your time.