In business-to-business telemarketing script writing, an often-used tactic is to use a survey as a means to gather qualifying information for follow-up marketing efforts. Sometimes, the transition from survey to lead generation takes place in the same call.
However, if you work in the business-to-consumer marketplace, beware the federal Telemarketing Sales Rule. One of the stipulations is that any sales call must be identified as such. If you switch from conducting a survey to pitching your product or service, you could face $16,000 in fines for each violation.
You can download the FTC legal document here: http://www.ftc.gov/os/2003/01/tsrfrn.pdf