plm (version 1.6-5)

is.pbalanced: Check if data are balanced

Description

This function checks if the data are balanced, i.e. each individual has the same time periods

Usage

"is.pbalanced"(x, ...)
"is.pbalanced"(x, index = NULL, ...)
"is.pbalanced"(x, ...)
"is.pbalanced"(x, ...)
"is.pbalanced"(x, ...)

Arguments

x

an object of class pdata.frame, data.frame, pseries, panelmodel, pgmm;

index

only relevant for data.frame interface; if NULL, the first two columns of the data.frame are assumed to be the index variables; if not NULL, both dimensions ('individual', 'time') need to be specified by index as character of length 2 for data frames, for further details see pdata.frame,

...

further arguments.

Value

A logical indicating whether the data associated with object x are balanced (TRUE) or not (FALSE).

Details

Balanced data are data for which each individual has the same time periods. The returned values of the is.pbalanced(object) methods are identical to pdim(object)$balanced. is.pbalanced is provided as a short cut and is faster than pdim(object)$balanced because it avoids those computations performed by pdim which are unnecessary to determine the balancedness of the data.

See Also

punbalancedness for two measures of unbalancedness, make.pbalanced to make data balanced; is.pconsecutive to check if data are consecutive; make.pconsecutive to make data consecutive (and, optionally, also balanced). pdim to check the dimensions of a 'pdata.frame' (and other objects), pvar to check for individual and time variation of a 'pdata.frame' (and other objects), pseries, data.frame, pdata.frame.

Examples

# take balanced data and make it unbalanced
# by deletion of 2nd row (2nd time period for first individual)
data("Grunfeld", package = "plm")
Grunfeld_missing_period <- Grunfeld[-2, ]
is.pbalanced(Grunfeld_missing_period)     # check if balanced: FALSE
pdim(Grunfeld_missing_period)$balanced    # same

# pdata.frame interface
pGrunfeld_missing_period <- pdata.frame(Grunfeld_missing_period)
is.pbalanced(Grunfeld_missing_period)

# pseries interface
is.pbalanced(pGrunfeld_missing_period$inv)