# Re: st: Counting shifts (and duration) in labor market status

 From Nick Cox <[email protected]> To [email protected] Subject Re: st: Counting shifts (and duration) in labor market status Date Tue, 29 Apr 2003 22:09:52 +0100

```Thomas

I have monthly labor market status observations: i.e each person is
observed
through 12 months with the following information: 1 employed, 2
unemployed, 3
out of labor force.
ex:

obs   Jan   Feb   Mar   Apr ................
1     2     2     1     1
2     1     1     1     2
3     1     2     2     3

I am now looking for a smart way of counting number of times each
person fell
into unemployment, i.e. a shift from 1 to 2 (or maybe even 3 to 2).
Also how to
count the duration of each unemployment spell i.e. how many months
does every
spell last.

I assume that many have encountered this issue before me and thought
of a smart
way to do it.

>>>

1. -reshape-
============

You need first to -reshape- to long. Your data structure problem is
described at

http://www.stata.com/support/faqs/data/reshape3.html

but you need, before that even, to -rename- those month
variables:

(Stata 8)

local i = 1
foreach v of var Jan-Dec {
rename `v' m`i++'
}

OR

(Stata 7)

for var Jan-Dec \ new m1-m12 : rename X Y

OR

(-renvars-, STB-60)

renvars Jan-Dec \ m1-m12

Now you

reshape long m , i(obs) j(time)

2. -tsset-
==========

Then you can

tsset obs time

3. -tsspell-
=============

(Stata 8 or updated Stata 7)

ssc inst tsspell

then

tsspell, fcond(m == 2 & L.m != 2)

or

tsspell m

and look at the resulting variables. The help file for -tsspell-
gives several examples.

Nick
[email protected]
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```