Factors related to non-response trajectories of children and adolescents in a long term follow-up study

Objectives: The Child and Adolescent Behaviors in Long-term Evolution (abbreviated as CABLE) project had to change data collection methods for these subjects as they advanced to higher level schools including elementary school, junior high school, senior high school, and college or university. The purpose of this study was to describe the trajectories of non-response during the 9 year follow-up and to analyze the socio-demographic factors related to those trajectories. Methods: CABLE commenced in 2001 and subjects were followed every year. They were 1st and 4lh grade students (sample sizes were 2853 and 2663 respectively) with parental consent in Taipei City and Hsin-Chu County. Non-response was defined as not responding to a questionnaire every year. We used the Group-based Trajectory Model to find non- response trajectories and related factors as stratified by cohorts. Results: Both cohorts showed four trajectories: continuing response (percentages in cohort 1 and cohort 2 were 73.4% and 76.0%, respectively), late non-response (11.2% and 5.4%), increasing non-response (9.3% and 8.2%), and early non-response but late response (6.1% and 9.7%). With continuing response as the reference group, those who lived in Taipei City, those whose parental education was lower than senior high school, and those whose parents were not married were more likely to be non- responsive. Conclusions: Using CABLE long term data to make implication should consider these socio-demographic differences with non-response trajectories.