Graph # Dummy variables

[oseroser]

Dear all,

I am new to both this forum as to Stata.
I have a question regarding how to graph dummy variables.

I have a dataset consisting of different firms and different firm years. I have two dummy variables namely 1 for divestititures (dumdiv) and 1 for acquisitions (dumacq)

I want to graph the frequency of the amount of dummy=1 , per year.
this is how the tabulate version looks (of 1 variable)

dumdiv
Year 0 1 Total

1992 1,002 92 1,094
1993 1,051 115 1,166
1994 1,076 110 1,186
1995 1,134 138 1,272
1996 1,160 155 1,315
1997 1,208 152 1,360
1998 1,230 187 1,417
1999 1,278 166 1,444
2000 1,455 176 1,631
2001 1,556 172 1,728
2002 1,556 182 1,738
2003 1,602 196 1,798
2004 1,593 197 1,790
2005 1,543 225 1,768
2006 1,492 228 1,720
2007 1,442 214 1,656
2008 1,487 164 1,651
2009 1,497 136 1,633
2010 1,434 148 1,582
2011 1,271 119 1,390

Total 27,067 3,272 30,339

so i want to graph the 3th column with the first one. and the same for acquisitions. (both in one graph)


Thank you very much!

[bukharin]

What kind of graph do you want (bar, scatterplot, line graph...)?

A bar graph is easiest because the frequency of the dummy==1 is equal to the sum of the dummy variables:
graph bar (sum) dumdiv, over(Year)

If you want to use a -twoway- plot type (such as a line graph) you're best to collapse the dataset into the table that you posted:
collapse (sum) dumdiv, by(Year)
line dumdiv Year

If you want to create the graph without destroying your original data you can use -preserve-, like this:
preserve
collapse (sum) dumdiv, by(Year)
line dumdiv Year
restore

[oseroser]

Perfect Bukharin, thank you, it works! But how do I do the same if i want just one graph with both my divestitures and Acquisitions?

[bukharin]

It's pretty much a simple extension of the above, eg:
graph bar (sum) dumdiv dumacq, over(Year)

or

preserve
collapse (sum) dumdiv dumacq, by(Year)
line dumdiv dumacq Year
restore