Longitudinal studies are based on...Over-time observationsOne point in time observationsCross observationsSectional observationsNone of the options are correct

Understanding Longitudinal Studies

Longitudinal studies are a type of observational research method that involve repeated observations of the same variables over an extended period of time. This method is particularly useful in various fields, including psychology, sociology, and medicine, as it allows researchers to track changes and developments in specific populations or phenomena.

Explanation of Options

1. Over-time observations: This is the defining characteristic of longitudinal studies, where data is collected from the same subjects repeatedly across multiple time points.

2. One point in time observations: This describes cross-sectional studies, which analyze data from a population at a single point.

3. Cross observations: This term is not commonly used in research methodology and does not specifically describe a type of study.

4. Sectional observations: Similar to the previous option, this term seems to refer to cross-sectional studies but is not a standard term.

5. None of the options are correct: This would imply that none of the definitions align with established research methodologies.

Final Answer

The correct answer is Over-time observations, as longitudinal studies specifically focus on gathering data from the same subjects over time to observe changes and developments.