RECENTLY a practice commonly used by survey research firms to precode questionnaires received widespread exposure in the national media. In an editorial called the "Invisible Ink Caper" (Gemmill, 1975: 22), a highly respected major newspaper stated that it had unknowingly taken part in the unethical practice of coding survey research questionnaires with ultraviolet ink in order to determine specifically who filled out each returned form. Normally respondents are explicitly assured that their responses will be either confidential or anonymous. 1 For instance, the cover letter accompanying the questionnaire may imply that the respondent's returned questionnaire will be completely anonymous. Therefore, precoding the questionnaire constitutes a violation of the "good faith" of the respondents.It is difficult to ascertain just how widespread this practice is. C. M. Crawford reported (1970) that when directors of marketing research were surveyed for a study, 29 percent of them approved of the use of ultraviolet ink in precoding "anonymous" surveys. However, it seems reasonable to conclude this figure is low because, as Crawford cautions in his report, when discussing ethics people tend to say what they think is publicly acceptable yet privately they do what is in their own best interest. A confidential response is made by a respondent whose identity is known but kept secret, whereas an anonymous response is made by an unidentifiable respondent.Editor's Note This article, unlike most POQ articles, is an expression of opinion rather than a report of research findings. Because of the increasing concern about ethical issues in research on the part of the public, government, and researchers themselves, we decided to print it and to invite comments from people who have been involved in one way or another either with public opinion research including mail surveys or with ethical and legal issues concerning research. The comments that follow the article were received at the time we went to press. We invite other comments from readers.John Dickson and William Wynd teach marketing at Eastern Washington State College. Michael Casey and Daniel WyckofTare investigators for the Attorney General's Office of the State of Washington.