Questions about Questionnaires?

Although I routinely use questionnaires during the User Analysis phase of my projects, I carefully explain to my Clients that the results have (at best) limited validity and reliability because I am not a research specialist. If I had my druthers (and budget!) I'd hire a trained researcher to create and administer surveys and questionnaires, but that's almost always a luxury—so I keep my amateur versions as simple as possible, loading my reports with caveats.

For those curious about the need for skillfully-crafted questionnaires, I'll sometimes refer them to Jurek Kirakowski's Questionnaires in Usability Engineering: A List of Frequently Asked Questions. It's a great introduction to the science of "questionneering" and clearly explains the pitfalls of poorly-designed instruments.