If the survey analysis validates suspected problems, accept it and take steps. If the results from a small sample seem totally off base, check the sampling methodology and do a retest. Less is more. Don't overload your survey with too many questions, complicated ranking or rating dozens of items. A good response rate to a survey covering an important area is better than a dismal response rate to a comprehensive survey.
Timing is everything.
Don't mail a survey when your members are vacationing or, conversely, in the middle of their busy season. Don't mail the survey with something else. Including the survey with another mailing, such as your newsletter, lowers the response rate. Don't tabulate the results manually. Consider investing in software specifically designed for nonprofit organizations' surveys.