Gretl Manual: Gnu Regression, Econometrics and Time-series Library
Prev | Chapter 7. Panel data | Next

# Illustration: the Penn World Table

The Penn World Table (homepage at pwt.econ.upenn.edu) is a rich macroeconomic panel dataset, spanning 152 countries over the years 1950–1992. The data are available in `gretl` format; please see the `gretl` data site (this is a free download, although it is not included in the main `gretl` package).

Example 7-1 below opens `pwt56_60_89.gdt`, a subset of the pwt containing data on 120 countries, 1960–89, for 20 variables, with no missing observations (the full data set, which is also supplied in the pwt package for `gretl`, has many missing observations). Total growth of real GDP, 1960–89, is calculated for each country and regressed against the 1960 level of real GDP, to see if there is evidence for "convergence" (i.e. faster growth on the part of countries starting from a low base).

Example 7-1. Use of the Penn World Table

    	  open pwt56_60_89.gdt
    	  # for 1989 (the last obs), lag 29 gives 1960, the first obs
    	  genr gdp60 = RGDPL(-29)
    	  # find total growth of real GDP over 30 years
    	  genr gdpgro = (RGDPL - gdp60)/gdp60
    	  # restrict the sample to a 1989 cross-section
    	  smpl --restrict YEAR=1989
    	  # convergence: did countries with a lower base grow faster?
    	  ols gdpgro const gdp60
    	  # result: No! Try an inverse relationship?
    	  genr gdp60inv = 1/gdp60
    	  ols gdpgro const gdp60inv
    	  # no again.  Try treating Africa as special?
    	  genr afdum = (CCODE = 1)
    	  genr afslope = afdum * gdp60
    	  ols gdpgro const afdum gdp60 afslope

Prev | Home | Next
Pooled estimation | Up | Graphs and plots