An evaluation of a self‐generated identification code

Abstract

We describe a self-generated coding form used in a study of HIV prevention practices of college students and provide information on the success rate of matching questionnaires over a 3-year period using the form. The data for this study were from a longitudinal study of HIV riskreduction practices of college students. In order to match questionnaires over the 3-year study period while maintaining anonymity, participants were asked to complete a self-generated identification form at each data collection point. In the second year of the project, we were able to successfully match 74.3% of the questionnaires to those returned during the first year using 6 to 8 of the code elements on the form, and in the third year, we were able to match 73% of questionnaires to those returned in the second year. Participants for whom questionnaires matched were more likely than participants with unmatched questionnaires to be white students enrolled as underclassmen.

Methodological Issues With Coding Participants in Anonymous Psychological Longitudinal Studies

“…Generally, participants are allowed to have at least one question not match between waves (one-off) or two questions not match between waves (two-off). With faulttolerant methods, data loss of 20% to 30% is not unusual, although less than 10% data loss is possible if the choice of questions is greatly simplified (DiIorio, Soet, Van Marter, Woodring, & Dudley, 2000;Kearney, 1982;Schnell, Bachteler, & Reiher, 2010). It should be noted that, when exact agreement between codes is required, losses of up to 50% of matched pairs are common (Schnell et al, 2010).…”

“…Instances of supposedly anonymous data being re-identified as coming from a particular university have occurred through a combination of such information as the total number of students in a class year, the nationalities represented, and the college majors offered (Zimmer, 2010). Third, as discussed in the previous method, the use of any personally identifying information is likely to affect the participant's confidence in the anonymity of the data they provide (DiIorio et al, 2000). For instance, Widrich and Ortlepp (1994) used full birthdate as a preexisting unique identifier.…”

“…First, if set up and used optimally, these systems will prevent identification of participants, which leads to the second benefit-that of reducing or preventing confirmatory bias. Third, participants are likely to view it as truly anonymous and respond in accord with that belief (Catania et al, 1990;DiIorio et al, 2000;Kearney, 1982;Schnell et al, 2010;Tregarthen et al, 2015). Fourth, if set up and used in consultation with technology and legal experts, electronic anonymizing systems can also facilitate researchers' ability to comply with various legal requirements to appropriately protect patients' privacy and confidentiality (Fisher, 2013).…”

“…First, SGICs are truly anonymous, as they are not preexisting identifiers and are created using data with sufficient variability and impersonality to prevent individual identification. Second, this increase in degree of as well as perception of, anonymity has been shown to increase the quality and quantity of responses from participants (DiIorio et al, 2000;Kearney, 1982). Third, the use of salient personal information to create the SGIC increases the potential for improved recall of the SGIC to facilitate matching across waves (DiIorio et al, 2000).…”

“…Second, this increase in degree of as well as perception of, anonymity has been shown to increase the quality and quantity of responses from participants (DiIorio et al, 2000;Kearney, 1982). Third, the use of salient personal information to create the SGIC increases the potential for improved recall of the SGIC to facilitate matching across waves (DiIorio et al, 2000). Three benefits of the use of SGICs relate to the quality of the research: the reduction in the potential for confirmatory bias as insufficient data to produce a chance re-identification will be gathered; increased compliance with laws and regulations as a result of not collecting personally identifying information, and utility across data formats (paper and electronic formats).…”