| 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, index = NULL, ...) ## S3 method for class 'panelmodel': pdim(x, ...) ## S3 method for class 'pdata.frame': pdim(x, ...)
x |
a data.frame, a pdata.frame or a panelmodel object, |
index |
see pdata.frame, |
... |
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="plm")
pdim(Wages, 595)
# Gasoline contains two variables which are individual and time indexes
# and are the first two variables
data("Gasoline", package="plm")
pdim(Gasoline)
# Hedonic is an unbalanced panel, townid is the individual index
data("Hedonic", package="plm")
pdim(Hedonic, "townid")
# An example of the panelmodel method
data("Produc", package="plm")
z <- plm(log(gsp)~log(pcap)+log(pc)+log(emp)+unemp,data=Produc,
model="random", subset = gsp > 5000)
pdim(z)