A<unk>  or panel<unk>  is a form of longitudinal<unk>  used in medicine and social science. It is one type of<unk>  design and should be compared with a cross-sectional<unk> .
A<unk>  is a group of people who share a common characteristic or experience within a defined period (e.g., are born, leave school, lose their job, are exposed to a drug or a vaccine, etc.). Thus a group of people who were born on a day or in a particular period, say 1948, form a birth<unk> . The comparison group may be the general population from which the<unk>  is drawn, or it may be another<unk>  of persons thought to have had little or no exposure to the substance under investigation, but otherwise similar. Alternatively, subgroups within the<unk>  may be compared with each other.
Cohort study
Longitudinal study
Randomized controlled trial
Clinical trial
Cross-sectional study
Systematic review
Longitudinal studies
Meta-analysis