pdim {plm} | R Documentation |
This function checks the number of individuals and time observations in the panel and whether it is balanced or not.
pdim(x,...) ## S3 method for class 'data.frame': pdim(x, indexes = NULL, ...)
x |
a "data.frame" or a "plm" object, |
indexes |
see plm.data , |
... |
further arguments. |
pdim
is called by the estimation functions.
an object of class pdim
containing the following elements :
nT |
a list containing n , the number of individuals,
T , the number of time observations, N the total number
of observations, |
TinT |
a list containing two vectors : Ti gives the
number of observations for each individuals and nt gives
the number of individuals observed for each period, |
balanced |
a logical value : TRUE for a balanced panel,
FALSE for an unbalanced panel, |
panel.names |
a list of character vectors : id.names
contains the names of each individual and time.names
contains the names of each period. |
Yves Croissant
#There are 595 individuals data("Wages", package="Ecdat") pdim(Wages, 595) # Gasoline contains two variables which are individual and time indexes # and are the first two variables data("Gasoline", package="Ecdat") pdim(Gasoline) # Hedonic is an unbalanced panel, townid is the individual index data("Hedonic", package="Ecdat") pdim(Hedonic, "townid")