First steps in Stata 4: Reshape

Now, one useful command whose use is almost unavoidable, “reshape”.

We were working with the data of Spanish inward foreign direct investment (First steps in Stata 1). You can download by clicking here. The original state of the database is the following:

desc

obs:       250                                             

vars:      23                                          

size:       54,000                                                  

                storage display  value

variable name   type       format  label      variable label

Country                str40      %40s                      Country

fdiflw1993           double  %10.0g                  fdiflw1993

fdiflw1994           double  %10.0g                  fdiflw1994

fdiflw1995           double  %10.0g                  fdiflw1995

fdiflw1996           double  %10.0g                  fdiflw1996

fdiflw1997           double  %10.0g                  fdiflw1997

fdiflw1998           double  %10.0g                  fdiflw1998

fdiflw1999           double  %10.0g                  fdiflw1999

fdiflw2000           double  %10.0g                  fdiflw2000

fdiflw2001           double  %10.0g                  fdiflw2001

fdiflw2002           double  %10.0g                  fdiflw2002

fdiflw2003           double  %10.0g                  fdiflw2003

fdiflw2004           double  %10.0g                  fdiflw2004

fdiflw2005           double  %10.0g                  fdiflw2005

fdiflw2006           double  %10.0g                  fdiflw2006

fdiflw2007           double  %10.0g                  fdiflw2007

fdiflw2008           double  %10.0g                  fdiflw2008

fdiflw2009           double  %10.0g                  fdiflw2009

fdiflw2010           double  %10.0g                  fdiflw2010

fdiflw2011           double  %10.0g                  fdiflw2011

fdiflw2012           double  %10.0g                  fdiflw2012

fdiflw2013           double  %10.0g                  fdiflw2013

fdiflw2014           double  %10.0g                  fdiflw2014

                                                                               

As it can be gathered, we have the amount of investment separately for each year, which can be useful for some type of regressions but not for others. The objective is to convert the 22 FDI variables into two, one that specifies the year of investment and the other that contains the flows of investment. In this case we use “reshape long”. The command is the following:

reshape “variable name without number”, i(unique identifier of each subject) j(period of time)

reshape long fdiflw, i(Country) j(year)

We will notice that now our database only has three variables (Country, year and fdiflw), by using the command describe (desc) you will get the following:

Then, if we want to go back to the original format of the data we do “reshape wide”    

reshape wide fdiflw, i(Country) j(year)