I analyze labour market activities. I measure
JD: job duration (time between beginning and ending of employment) and
PD: professional duration (the time spent in a specific vocation). My sample is episode based (not individual based), thats important for
PD: I measure
PD as two subsequent job episodes in the same vocation.
PD therefore is greater than or equal to
JD by definition. Furthermore I have more data points for
JD (every single employment gives a data point) than for
PD (for every employee two subsequent employments in the same vocation are merged to one data point).
I am interested in the difference between
PD and I want to compare this difference for multiple groups.
JD and separately
PD isn't desirable. Suppose group
A has a short
JD and a slightly longer
B could then have a long
JD but a
PD that's only slightly longer than
JD. What test can be performed to check for a difference of the difference between
Does it makes sense to test for a difference in proportions of
PD in groups?
Non-sequitor: what does the
rho do in
survdiff-test and how should I choose
My approach still seems unclear. Here's what I do exactly:
I use a database storing people's id (
ID), begin data of an occupation (
BEGIN), end date of an occupation (
END) and type of occupation (
- To gather
ENDand build different groups using
- To receive
PDI do the following: For every
IDif 2 subsequent employments (
e2) have the same
TYPE, I merge them to one episode (with
END(e2)). I repeat this step until no more merges are possible (e.g. if there are 3 subsequent employments (
e3) of the same
TYPE, I end up with one episode (with
Finally, what I try to find out is, if the difference between
PD follows a similar pattern for different types or not.