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FGC--The Gambia: DHS 6--2013. [message #10532] Wed, 03 August 2016 03:01 Go to next message
Jawla is currently offline  Jawla
Messages: 7
Registered: August 2016
Member
I am conducting analysis on attitudes towards FGC using the women data set with Stata. I have a question on weight.
Primary sampling unit v021
Sample strata v022
Women individual sample weight or the pw v005/1000000
fpc/10,233

Hence, this is a two stage stratified cluster sampling. Should I be worried about the secondary sampling unit and which variable is that? Do I need the househould dataset for this? How relevent is the v020 in the women data set. Should I use the single stage or multi stage stata syntax.Thanks!


Best, Jawla.
Re: FGC--The Gambia: DHS 6--2013. [message #10560 is a reply to message #10532] Mon, 08 August 2016 09:43 Go to previous messageGo to next message
Liz-DHS
Messages: 1516
Registered: February 2013
Senior Member
A response from Shireen Assaf:
Quote:

Hello Jawla,
In DHS we have a multi stage stratified sample design with one strata variable v022 or v023 as you indicated. There is no need to use fpc. You can set up the svyset for your analysis as follows:
gen wt =v005/1000000
svyset v021 [pw=wt], strata(v022) singleunit(centered)

Thank you.

Best,

Shireen Assaf (DHS Senior Research Associate)

Re: FGC--The Gambia: DHS 6--2013. [message #10563 is a reply to message #10560] Tue, 09 August 2016 01:37 Go to previous messageGo to next message
Jawla is currently offline  Jawla
Messages: 7
Registered: August 2016
Member
Thank you so much, Shireen, I very much appreciate your prompt response to my question.
Best, Jawla.


Best, Jawla.
Re: FGC--The Gambia: DHS 6--2013. [message #10584 is a reply to message #10563] Fri, 12 August 2016 22:42 Go to previous messageGo to next message
Jawla is currently offline  Jawla
Messages: 7
Registered: August 2016
Member
Shireen,

I played with the data after trying:
svyset v021 [pw=wt], strata(v022) singleunit(centered)

(Did not need to use -- gen wt =v005/1000000 -- as wt is already defined.)

after playing with some tabulation, the "population size" is still coming out approximately the same as the "number of observations." I think there is a problem -- I may be wrong. Evidence that I could be wrong is that a simple tab and a tab that includes the probability weights yield different answers. For example:

tab g119 [iweight=wt]

Female |
circumcision: |
continue or |
be stopped | Freq. Percent Cum.
--------------+-----------------------------------
1. Continued | 6,594.629 64.96 64.96
2. Stopped | 3,392.317 33.42 98.38
8. Don't know | 161.738423 1.59 99.97
9 | 3.19361798 0.03 100.00
--------------+-----------------------------------
Total | 10,151.878 100.00

. tab g119

Female |
circumcision: |
continue or |
be stopped | Freq. Percent Cum.
--------------+-----------------------------------
1. Continued | 6,305 62.12 62.12
2. Stopped | 3,674 36.20 98.32
8. Don't know | 165 1.63 99.94
9 | 6 0.06 100.00
--------------+-----------------------------------
Total | 10,150 100.00

However, as the Stata manual says better than I could:
pweights, or sampling weights, are weights that denote the inverse of the probability that the observation is included because of the sampling design.

So it seems to me that the population size reported in tabulations should be much higher than the number of observations used to create that tabulation.

Why is that when you do a two-way tabulation (for example),the number of observations and the population size are reported to be very similar to one another?

Thank you and I look forward to hearing from you at your earliest convenience.
Best, Jawla.


Best, Jawla.
Re: FGC--The Gambia: DHS 6--2013. [message #10678 is a reply to message #10584] Mon, 29 August 2016 14:18 Go to previous messageGo to next message
Liz-DHS
Messages: 1516
Registered: February 2013
Senior Member
A response from Technical Specialist, Shireen Assaf:
Quote:

Dear Jawla,

In the DHS we perform a normalization so that the weighted and unweighted totals are the same.
Perhaps the following DHS online video tutorials on sampling and weighting can help: https://www.youtube.com/watch?v=DD5npelwh80&list=PLagqLv -gqpTN8IZQBy7vAYw10NjynAn2Z

Also in your code, you have set up the svyset but have not used it. If you run the svyset then you can use svy: ta g119 . There is no need to write ta g110 [iw=wt] if you use svy.

Best,

Shireen

Re: FGC--The Gambia: DHS 6--2013. [message #10685 is a reply to message #10678] Mon, 29 August 2016 22:11 Go to previous message
Jawla is currently offline  Jawla
Messages: 7
Registered: August 2016
Member
Dear Shireen,
Thank you so much for your follow up on this matter. This is very much appreciated! I will keep you posted if I encounter any further issue with the DHS data.
Best, Jawla,


Best, Jawla.
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