When researchers study a specific well-defined population over time sampling different people at each data collection point, it refers to a

The correct answer is Cohort study.

Important Points

In a cohort study, the researchers select a group of individuals who share a common characteristic (such as age, occupation, exposure to a specific factor, etc.) and then follow them over an extended period. This study aims to observe and analyze how certain factors or exposures may influence the development of specific outcomes or diseases over time.

Cohort studies are particularly useful for studying the incidence of diseases, identifying risk factors, and determining cause-and-effect relationships between exposures and outcomes. They provide valuable longitudinal data and allow researchers to assess changes and trends within the cohort over time.

 Additional Information 

A panel study is a type of longitudinal study in social and behavioral sciences where a group of individuals, households, or entities (the panel) is surveyed or observed repeatedly over an extended period. The same participants are re-interviewed, re-examined, or re-observed at multiple time points, allowing researchers to track changes and developments within the group over time.

Cross-sectional study:

• A cross-sectional study is a research design that collects data from a population or sample at a specific point in time. It aims to gather information about the prevalence or characteristics of a condition or phenomenon at a specific moment.
• Unlike panel studies, cross-sectional studies do not involve following individuals over time but instead gather data from different individuals at a single time point.

Retrospective study:

• A retrospective study looks back at past events or data to analyze the relationship between exposure or factors and outcomes.
• It involves collecting and analyzing data from the past, often relying on existing records or information. Retrospective studies do not necessarily involve following a specific population over time.