High Quality Content by WIKIPEDIA articles! In statistics and econometrics, the term panel data refers to two-dimensional data. Data is broadly classified according to the number of dimensions. A data set containing observations on a single phenomenon observed over multiple time periods is called time series. In time series data, both the values and the ordering of the data points have meaning. A data set containing observations on multiple phenomena observed at a single point in time is called cross-sectional. In cross-sectional data sets, the values of the data points have meaning, but the ordering of the data points does not. A data set containing observations on multiple phenomena observed over multiple time periods is called panel data. Panel Data aggregates all the individuals, and analyzes them in a period of time. Alternatively, the second dimension of data may be some entity other than time. For example, when there is a sample of groups, such as siblings or families, andseveral observations from every group, the data are panel data. Whereas time series and cross-sectional data are both one-dimensional, panel data sets are two-dimensional.