Before venturing out to build your own survey, consider what is already out there. Look for things like: Industry recognition, detail level of available information, flexibility in adding and removing questions, and ability to compare your customer satisfaction to others within and outside the industry.
If you build your own survey, the same questions (above) are still relevant. But, also make sure the survey is simple enough that it is likely to be understood and completed. Also ensure you as well as the vendor has access to the survey results. Outsourcing vendors, who have the appropriate sticks and carrots, can drive your customer satisfaction in innovative ways that would be unlikely or impossible within your core organization. Isn't that a key reason for contracting with the vendor in the first place?
What to do with all that customer satisfaction results information? In the next couple of articles, we'll discuss what to do with it to drive your business. For now, here's what not to do, (but is done all to often)... look at one or two customer satisfaction results that justify your preconceived ideas of what is wrong and then force change based on your "analysis." I'm not saying you'd do that, but that other company might.