Re: st: Survey - raking - calibration - post stratification - calculating weights

[Steven Samuels <sjhsamuels@earthlink.net>]

--

Kristian, before I can answer your questions, I need details of how  
you selected the original 5,000 men.  Describe the target  
population;  the sampling "frame" (or list) from which you drew the  
sample of 5,000; what information you have about the population (age  
distribution, for example); what information about each man on the  
list was available; exactly how you selected the 5,000.   Also, what  
is the purpose of the study?  Why did you seek equal numbers of men  
in the 15 age groups at later stages?


-Steve
> questionaire.
On Dec 6, 2008, at 5:32 AM, Kristian Wraae wrote:

> Hello all
>
> I have a question regarding how to weight a data set.
>
> The data is from a population based cross sectional study.
>
> 5000 randomly selected men reflecting the backgound population were  
> mailed a
> questionaire.
>
> 75% responsrate. 3750 questionnaires filled out. We know the age  
> and the zip
> code for non-responders.
>
> The questionnaire contained several sociodemographic parameters s1,  
> s2,
> ..... Sn
>
> Then 1845 men from the group that had filled out a questionnaire were
> invited to take part in a scientific project. The men were randomly  
> selected
> with an equal number in each age group (15 age groups of one year
> intervals). So 123 men in each group.
>
> 946 men accepted a telephone call. 768 men never responded and 131  
> refused
> to be interwied on telephone.
>
> 864 men of the 946 were then randomly contacted with equal numbers  
> in each
> age group and 697 men agreed to take part in the project. 97 men later
> cancelled or never showed up.
>
> So 600 men were included for further studies.
>
> Now I would like to weight these 600 men so they reflect the  
> background
> population in order to estimate the distribution of different  
> measures in
> the background population (X1, X2, .... Xi) based on measures  
> amongst the
> 600 men (Y1, Y2, ..... Yi).
>
> How do I do this?
>
> As far as I can tell I need to compensate for the differences  
> between the
> 5000 and the 3750 and between the 3750 and the 600. Since the 1845  
> were
> randomly selected and an equal number in each age group were  
> contacted I
> assume that all men had an equal probability of being included so  
> design
> weights are not really needed. Right?
>
> But how do I compute a pweight that takes the two steps into account?
>
> I have looked a bit a the SURVWGT command in stata but I don't  
> understand
> it.
>
> Could someone help me with some examples.
>
> Thanks
> Kristian
>
>
>
>
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