Which term describes data collected over several time periods for the same units?

Which term describes data collected over several time periods for the same units?

• A. Categorical Data
• B. Longitudinal (time-series) data
• C. Imputation
• D. Data Scaling

Answer: (B)

Longitudinal data refers to data collected over several time periods for the same units. This design follows the same subjects or entities across multiple points in time, which lets you observe how each unit changes and how these changes unfold across the population. It’s different from a single-unit time-series, which tracks one unit over time, and from cross-sectional data, which captures different units at one point in time. The other options don’t describe this structure: categorical data are qualitative categories, imputation is about filling in missing values, and data scaling involves adjusting the range or distribution of variables for analysis.

Longitudinal data refers to data collected over several time periods for the same units. This design follows the same subjects or entities across multiple points in time, which lets you observe how each unit changes and how these changes unfold across the population. It’s different from a single-unit time-series, which tracks one unit over time, and from cross-sectional data, which captures different units at one point in time.

The other options don’t describe this structure: categorical data are qualitative categories, imputation is about filling in missing values, and data scaling involves adjusting the range or distribution of variables for analysis.