Panel data

Panel data (panel　Data) is the data collected by different observation objects in different time periods or time points, describing the changes of multiple observation objects with time. For example, the GDP of all provinces, autonomous regions and municipalities in China from 2010 to 2020. For panel data, if only a certain time period or time point is considered, it is cross-sectional data; If only one observation object is considered, it is time series data.