Longitudinal Study

Also known as: Panel Study, Tracking Study, Longitudinal Research

Research measuring the same variables in the same sample or population over time to detect changes and trends.

A Longitudinal Study is research that measures the same variables in the same sample (panel) or comparable samples of the same population at multiple time points, with the goal of detecting changes, trends, and causal relationships.

In market research, the most common longitudinal studies are Brand Trackers (measuring brand metrics continuously or periodically), purchase panels (tracking purchase behavior of the same households over time), and customer satisfaction studies.

The main advantage of the longitudinal design over the cross-sectional design is that it allows distinguishing real changes in the population from cohort differences, and establishing temporal causality ('A happened before B').

Atlantia designs all its Brand Trackers as longitudinal studies to capture trends and evaluate the impact of marketing actions.