Opportunities and Challenges with Longitudinal Studies in the Youth Development Sector

Investing in holistic youth development in low-and-middle-income countries (LMICs) is essential to promoting long-term economic growth, democracy, and stability and advancing sustainable, inclusive development. Thus, it is imperative to conduct research and evaluation (R&E) activities to better understand what interventions and approaches work to improve long-term outcomes for youth. In line with USAID’s Positive Youth Development (PYD) framework, this includes approaches that build skills, assets, autonomy, and competencies; promote youth engagement and leadership; foster healthy relationships; strengthen the environment; and transform systems.

Longitudinal studies, which capture how a situation persists or changes over time and how these changes impact individuals and communities, are a critical tool for generating evidence in the youth development sector. A longitudinal study follows a group of participants—who may be randomly or purposefully selected depending on the study design—over time to gather data on outcomes of interest. Data collection time points for longitudinal studies can range from every few months to several decades; the duration and frequency will depend on the phenomenon under study and funding considerations. However, as time progresses, the challenge of tracing original participants becomes increasingly difficult.

 Attrition—where participants drop out of a study over time—is a real concern for longitudinal studies, as it threatens study validity, statistical power, and potentially leads to biased results that do not accurately represent outcomes. Attrition can be influenced by factors within and outside of researchers’ control, including mode of engagement with participants, types of data collected for potential future follow-up, participant emigration, health status, or other characteristics. For longitudinal surveys in LMICs, participants moving after baseline is the primary contributor to non-response. Attrition is a more significant challenge for studies with young people, in part due to mobility and issues with maintaining their engagement in study activities, given various other changes and milestones they may be experiencing in their lives. This challenge is often exacerbated for marginalized youth, as the characteristics that contribute to youth’s marginalized status—such as displacement due to crisis or conflict, unemployment, or safety concerns related to identity—may also make it difficult to continue participation in a study over time.

To fully realize the value of longitudinal research and the extent to which it can contribute evidence to improve youth programming, strategies to minimize attrition are critical. This guidance note describes approaches used to track youth participants over time across multiple studies conducted under the YouthPower2: Learning and Evaluation (YP2LE) activity. This summary supplements existing literature on longitudinal studies with young people and highlights promising practices, lessons learned, and recommendations for future R&E activities with youth