Which of the following is NOT a feature of longitudinal research design?

Longitudinal research design is characterized by the collection of data over an extended period, allowing researchers to study changes and developments in the same subjects, making it different from other research designs. One of the key features is that data can be ordered over time, providing insights into trends and patterns, as it captures how individuals or groups evolve throughout the study period.

Repeated measurements are also a significant aspect, as longitudinal studies often involve collecting data from the same participants multiple times. This approach enables researchers to observe changes and establish causal relationships more effectively.

The correct answer identifies that longitudinal research does not imply collection at one specific point in time. This is a critical distinction, as the essence of longitudinal studies is to track changes over time rather than capturing a snapshot that ignores variations and developments that might occur. Lastly, while longitudinal studies typically track changes in the same sample over time, they do not inherently involve tracking changes across different samples, making this design unique in its focus on consistent subjects for measurement.