nobs.plm

0th

Percentile

Extract Total Number of Observations Used in Estimated Panelmodel

This function extracts the total number of 'observations' from a fitted panel model.

Keywords
attribute
Usage
# S3 method for panelmodel
nobs(object, ...)

# S3 method for pgmm nobs(object, ...)

Arguments
object

a panelmodel object for which the number of total observations is to be extracted,

further arguments.

Details

The number of observations is usually the length of the residuals vector. Thus, nobs gives the number of observations actually used by the estimation procedure. It is not necessarily the number of observations of the model frame (number of rows in the model frame), because sometimes the model frame is further reduced by the estimation procedure. This is e.g. the case for first--difference models estimated by plm(..., model = "fd") where the model frame does not yet contain the differences (see also Examples).

Value

A single number, normally an integer.

See Also

pdim()

Aliases
  • nobs.plm
  • nobs.panelmodel
  • nobs.pgmm
Examples
# NOT RUN {
# estimate a panelmodel
data("Produc", package = "plm")
z <- plm(log(gsp)~log(pcap)+log(pc)+log(emp)+unemp,data=Produc,
         model="random", subset = gsp > 5000)
         
nobs(z)       # total observations used in estimation
pdim(z)$nT$N  # same information
pdim(z)       # more information about the dimensions (no. of individuals and time periods)

# illustrate difference between nobs and pdim for first-difference model
data("Grunfeld", package = "plm")
fdmod <- plm(inv ~ value + capital, data = Grunfeld, model = "fd")
nobs(fdmod)      # 190
pdim(fdmod)$nT$N # 200

# }
Documentation reproduced from package plm, version 2.2-5, License: GPL (>= 2)

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