Using Security Questions to Link Participants in Longitudinal Data Collection


Anonymous data collection systems are often necessary when assessing sensitive behaviors but can pose challenges to researchers seeking to link participants over time. To assist researchers in anonymously linking participants, we outlined and tested a novel security question linking (security question linking; SEEK) method. The SEEK method includes four steps: (1) data management and standardization, (2) many-to-many matching, (3) fuzzy matching, and (4) rematching and verification. The method is demonstrated in SAS with two samples from a longitudinal study of adolescent dating violence. After an initial assessment during a laboratory visit, participants were asked to complete an online assessment either (a) once, 3 months later (Sample 1, n = 60), or (b) three times at 1-month intervals (Sample 2, n = 140). Demographics, eye color, and responses to nine security questions were used as key variables to link responses from the laboratory and online follow-up assessments. The rates of matched cases were 100% in Sample 1 and from 94.3 to 98.3% in Sample 2. To quantify the confidence in the data quality of successfully matched pairs, we reported the means and standard deviations of the number of matched security questions. In addition, we reported the rank order and counts of the mismatched components in key variables. Results indicate that the SEEK method provides a feasible and reliable solution to link responses in longitudinal studies with sensitive questions.

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Support for the Dating Study data collection was provided by Grants 2014-VA-CX-0066 and 1R21HD077345. We thank Gabriella Damewood, Ashley Dills, Nicole Graziano, and Angela Marinakis for their assistance in data collection.

Funding Information

The third author received research grants from the National Institutes of Health (1R21HD077345) and the National Institute of Justice (2014-VA-CX-0066) to support this study.

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Correspondence to Shu Xu.

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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

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Informed consent was obtained from all individual participants included in the study.

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The first, second, and fourth authors declare that they have no conflict of interest.

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Xu, S., Chan, A., Lorber, M.F. et al. Using Security Questions to Link Participants in Longitudinal Data Collection. Prev Sci (2019) doi:10.1007/s11121-019-01080-8

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  • Security questions
  • Linking
  • Longitudinal studies
  • SEEK
  • Online studies