Opinion Dynamics has conducted numerous mail surveys, and has developed a proven quality control system that is easily adapted to each new project. We provide a unique identification number to each survey, enabling us to track each respondent. From the time the survey questionnaire is completed to the final review, coding and key-punching, we pay close attention to every detail of the survey process. Quality control is extremely important when dealing with mail questionnaires. Quality control includes checking for inconsistencies in responses, looking for implied responses, and preparing the questionnaire for data entry. Without carefully reviewing the completed questionnaires, mail surveys can result in a lot of useless data. We examine and double-check all stages of coding, data entry and the verification process, by taking the following measures:

• Codes are established for open-ended questions, which are approved by the ODC project manager;
• Experienced staff code open-ended questions;
• The data is scanned to eliminate values outside allowable ranges.

ODC pays careful attention to the design and management of all mail surveys we conduct. We use our own full-time experienced support staff to prepare all mailings. For some mail surveys, we can also provide respondents with a link to a webpage that allows them to answer the survey online. This both increases the response rate while reducing potential response biases.