Time Classification of Research Designs
Non-experimental designs are often further classified according to timing of data collection as either cross-sectional or longitudinal, or according to the timing of the experience or event being studied as either retrospective or prospective. In a cross-sectional study, variables are identified one point in time and the relationships between them are determined. In a longitudinal study, data are collected at different points over time. In a retrospective study, an event or phenomenon identified in the present is linked to factors or variables in the past. In a prospective study, or cohort study, potential factors and variables identified in the present are linked to potential outcomes in the future.