Mail surveys are the backbone of customer satisfaction and quality tracking research. Over the past two decades, RDA Group has conducted considerable research-on-research, to find ways to improve the effectiveness of the mail methodology.

• Mail survey research offers attractive economies of scale. A large number of surveys can be sent out for a very reasonable cost, compared with other methodologies.
• Mail surveys can reach those who may not be accessible by telephone, particularly in an era of Caller ID and Call Screening.
• Mail surveys can utilize complex scales and can deal with complex concepts (assuming the person constructing the survey is skilled in simplifying complex concepts).
• Mail surveys can incorporate exhibits, although limited in size.
• Response rates can be quite attractive for certain industries. Mail surveys of new vehicle purchasors or leasees can result in up to 50% response rate with an incentive.

• Response rates on randomly drawn samples may yield poor response rates (as low as 10%), which means that non-response bias becomes an issue. Are the 90% that did not answer your survey different in some way than the 10% that did? If they are, your mail survey is not from a random sample of the population. Studies have shown little non-response bias at higher response rates (40% to 50%).
• It is impossible to know if the intended recipient actually filled out the survey, or whether someone else in the household did.
• Incomplete answers are unusable, and there is no interviewer to clarify or probe responses.