Survey research in different fields is a valuable input to management decision making. However, research is not an infallible tool that will always guarantee right decisions. But neither should it be replaced by decision making based solely on manager’s personal feelings. In this book the advantages and shortcomings of mail and online survey are discussed. The emphasis is on these quantitative methods because they behold many similarities from the perspective of respondents, the most important of which is the lack of interviewer presence. Therefore, they present a great challenge to researchers because the questionnaire design can influence the whole outcome of the survey. The author demonstrates that it is possible to lessen measurement and non-response errors with effective questionnaire design of self-administered surveys. The main principles on how to ask questions, what are the criteria for and how to construct a respondent-friendly questionnaire, and how to pretest the questionnaire are specified. The analysis and examples presented are useful for all types of managers, specialists and researchers who are involved in decision-making processes.