Unit
- Origins: Mail surveys trace back to the early 19th century when census bureaus first used postal questionnaires to collect demographic data from remote areas. The method gained scientific rigor in the 1930s with the advent of probability sampling.
- Mid-century adoption: By the 1950s, market research firms widely adopted mail surveys for consumer panels. The simultaneous growth of direct marketing provided infrastructure for mass mailing and address lists.
- Response rate decline: During the 1970s and 1980s, increasing mailbox clutter and telemarketing competition caused response rates to drop from over 60% to around 20% for unsolicited surveys.
- Total Design Method: Don Dillman pioneered the Tailored Design Method in the 1970s, introducing principles like personalized cover letters, respondent-friendly questionnaires, and multiple follow-ups to boost response.
- Technological shift: The 1990s brought computerized mail merge, barcode tracking, and optical scanning, reducing manual labor and enabling larger-scale operations with faster turnaround.
- Internet competition: Online surveys emerged in the late 1990s, offering lower cost and speed. Mail surveys adapted by focusing on populations with limited internet access, such as seniors and rural residents.
- Current niche: Today, mail surveys serve specialized sectors: B2B studies where executives prefer paper, healthcare patient satisfaction, and official government censuses. Response rates average 10-15% for cold mailings, higher for named contacts.
- Hybrid approaches: Modern mail operations often integrate with digital channels: pre-mailing emails, QR codes linking to online versions, and scannable paper forms that feed directly into databases.
- Sampling strategies: Address-based sampling (ABS) from the USPS delivery sequence file now provides near-complete coverage. Researchers overlay demographic data to target specific segments, such as households with seniors or high-income residents. Stratified sampling ensures adequate representation across geographic or socioeconomic groups.
- Incentive design: Prepaid incentives like cash (typically $1 to $5) or small gift cards yield higher response than promised rewards. Nonmonetary offers such as entry into a prize drawing can reduce costs but generate lower returns. Tailoring the incentive to the audience, for example a donation to a local charity, can further improve participation.
- Questionnaire layout: Optimal formatting includes a clean font no smaller than 10 point, generous white space, and a single-column layout to reduce skipping. Researchers recommend placing sensitive questions near the end and using branch instructions sparingly. Pilot testing with a small sample catches confusing wording or visual clutter.
- Address quality and undeliverables: Using the National Change of Address (NCOA) database before mailing removes known movers and reduces wasted postage. Including an address correction requested endorsement allows the USPS to forward or update addresses. Undeliverable rates average 5-10% for general lists but can be halved with periodic list cleaning.
- Data entry and verification: Optical mark recognition (OMR) and intelligent character recognition (ICR) capture responses from scannable forms. Human key entry remains common for handwritten open ends. Double entry verification, where two operators enter the same data and discrepancies are resolved, catches errors and ensures accuracy rates above 99%.
Campaign Case Study
Campaign: Greenfield Health Survey
Objective: Assess community health needs for a regional healthcare provider, targeting households in a three-county rural area.
Target Audience: Adults aged 40 and older, with limited internet connectivity, requiring paper-based data collection.
Channels: First-class mail with personalized cover letters, a self-addressed stamped envelope, and a $2 bill incentive included upfront.
Results: The survey achieved a 42% response rate after two follow-up postcards and a replacement questionnaire. Data was scanned and analyzed within three weeks. Illustrative outcomes show high completion rates for health-related questions.
Quick Revision
- Mail surveys originated in census operations and evolved with direct marketing infrastructure.
- Dillman's Tailored Design Method introduced key response-boosting techniques.
- Technological advances like scanning reduced manual processing.
- Current mail surveys focus on niche populations and hybrid digital integration.