# panel data

# Panel data
A combination of time series data and crossectional data is called panel data.
The panel data is also called longitudinal data.
## Different types of panel data
### Balanced  panel data
An equal number of observations for each entire period is called balance panel data
### Micro or short panel data:
The number of firms is more than the number of periods.
### Macro or long panel data:
The number of periods is more than the number of firms.
### Unbalanced panel data:
The number of observations is not the same for all subjects (firm, variable, etc.)