[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# st: RE: First difference in multidimensional panel

 From "Nick Cox" To Subject st: RE: First difference in multidimensional panel Date Fri, 24 Apr 2009 17:27:11 +0100

```Kit Baum and Martin Weiss both quite rightly pointed to -egen, group()-.

In addition, note that typing

. search identifier, faq

would have, among other things, identified this FAQ

FAQ     . . . . . . . . . . . . . . . . . . . . . . Creating group
identifiers
3/01    How do I create individual identifiers numbered
from 1 upwards?
http://www.stata.com/support/faqs/data/group.html

which also mentions -egen, group()- and, more importantly, explains the
logic behind it.

Reminder: -search- in your Stata points to many sources of information.

Nick
n.j.cox@durham.ac.uk

mm3040@columbia.edu

I have a panel data of share of intra-firm imports (s_{ict}) where
observations vary over industry (i), country (c) and time (t). I need
to calculate the first difference of s_{ict}:
Delta_s_{ict}=s_{ict}-s_{ic(t-1)}.
I am not sure how to do this since I do not have a unique panel
variable.
Also when using tsset how do I create unique id for each
industry-country pair (where both industry and country are string
variables). Any help would be appreciated.

My data is of the following form: Industry(Ind) and Country (Cty) are
both string variables
Ind Cty Yr
1 A 2000
1 B 2000
1 C 2000
1 A 2001
1 B 2001
1 C 2001
1 A 2002
2 A 2000
2 B 2000
2 D 2000
2X B 2001
2X A 2002
2X B 2002

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```

 © Copyright 1996–2015 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index