Re: st: Cox proportional hazard model

[Michael McCulloch <mm@pinestreetfoundation.org>]

Nyasha, Maarten explained very well the nature of what data you'd need  
to to time-to-employment analysis, which it turns out you can't  
measure in the context of your current project. This means you can't  
do survival analysis like the Cox method.

Another alternative analysis strategy is to instead study the  
likelihood of a person getting a job within some pre-determined time  
frame, using logistic regression. The dependent variable then is  
getting employment (yes/no), and the predictor variables are things like
		food aid
		use of AIDS medication
		and other characteristics of the person or household
Michael


On Aug 12, 2010, at 3:06 PM, Nyasha Tirivayi wrote:

> Dear Maarten
>
> Thanks for clarifying. Now I understand. I had this wrong. In that
> case I think I need to ask for ideas for alternative method since I do
> not have data on employment/unemployment spells.
>
> I have realized that I have 2 period panel data on employment status.
> So I have employment1 and employment2. I am interested in seeing the
> effects of AIDS medication  on transitions from one state to another.
>
> I also have another treatment variable- food aid. So you have some
> households where a patient is on AIDS medication and household
> receives food assistance. If I choose instead to look at the effect of
> food assistance ( meaning all households in analysis will now have a
> patient on AIDS medication), what kind of transition analysis can I
> do.. or maybe I should simply carry out multiple regression analysis
> or propensity score matching?
>
> Kindly advise
>
> Regards
>
> Nyasha Tirivayi
> Maastricht University
>
> On Thu, Aug 12, 2010 at 11:56 PM, Maarten buis <maartenbuis@yahoo.co.uk 
> > wrote:
> > --- On Thu, 12/8/10, Nyasha Tirivayi wrote:
> > > So the duration of the AIDS medication taken by the patient
> > > is the time variable, and getting employed/returning to work
> > > is the event
> >
> > The time variable and the event are not two separate concepts,
> > the duration is the time till the event occurs. When you look
> > at time till employment, then starting AIDS medication is not
> > the beginning of a spell, leaving the labor market, leaving
> > school, becoming unemployed, are the beginning of the spell.
> > Whether or not the patient takes AIDS medication is your
> > explanatory variable, not your explained variable.
> >
> > Hope this helps,
> > Maarten
> >
> > --------------------------
> > Maarten L. Buis
> > Institut fuer Soziologie
> > Universitaet Tuebingen
> > Wilhelmstrasse 36
> > 72074 Tuebingen
> > Germany
> >
> > http://www.maartenbuis.nl
> > --------------------------
> >
> >
> >
> >
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Best wishes,

Michael McCulloch, LAc MPH PhD
Pine Street Foundation
124 Pine Street
San Anselmo, CA 94960-2674
tel:	415-407-1357
fax: 	206-338-2391

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