Longitudinal research designs involve data collection at multiple time points to measure change over time. Therefore, identification of the same respondents is essential at each time point so that data from the same respondents can be matched for comparison over time. Subject-generated identification codes permit an anonymous means to track respondents over multiple data collection points. This article describes the evolution of subject-generated identification codes, techniques to improve respondent match rates, and the authors' experience using this mechanism in a longitudinal study of staff registered nurses working in hospitals. Challenges, recommendations, and implications for using subject-generated identification codes are discussed.

Decisional involvement is widely recognized as an essential component of a professional nursing practice environment. In recent years, researchers have added to the conceptualization of nurses' role in decision-making to differentiate between the content and context of nursing practice. Yet, instruments that clearly distinguish between these two dimensions of practice are lacking. The purpose of this study was to examine the factorial validity of the Decisional Involvement Scale (DIS) as a measure of both the content and context of nursing practice. This secondary analysis was conducted using data from a longitudinal action research project to improve the quality of nursing practice and patient care in six hospitals (N = 1,034) in medically underserved counties of Pennsylvania. A cross-sectional analysis of baseline data from the parent study was used to compare the factor structure of two models (one nested within the other) using confirmatory factor analysis. Although a comparison of the two models indicated that the addition of second-order factors for the content and context of nursing practice improved model fit, neither model provided optimal fit to the data. Additional model-generating research is needed to develop the DIS as a valid measure of decisional involvement for both the content and context of nursing practice.