SAS results exemplar 4

 This is an HTML version of the SAS program ex4.sas
 To run the program you must read ex4.do into the Stata do file editor
 to view the ouptut from these commands in html go to Stata results page

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Equal opportunities policies weighted and unweighted - Table 4.3
E O policy by workplace size Table 4.4
Other factors by equal opportunities policy Table 4.5
Logistic regressions Table 4.6
Logistic regressions  Table 4.7
Finite population corrections Table 4.8



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/*-----------------------------------------------------------
         Table 4.3
get unweighted estimate of proportion of
workplaces with an equal opportunities policy (EOP)
but allowing for stratification
-------------------------------------------------------------*/
gen const=1
svyset [pweight=const], strata(strata)
/*----------------------------------------------------------
now get weighted estimate - strata remain from previous call
using svymean to get design effect
------------------------------------------------------------*/
svyset [pweight=est_wt]
svydes
svyprop eo
svymean eo,deff deft
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/*--------------------------------------------------------------
         table 4.4
now weighted table of proportions woth EOP by size of workplace
------------------------------------------------------------*/
svytab  nempsize eo, row percent
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/*-------------------------------------------------------
         table 4.5
factors compared between eo workplaces and others
-------------------------------------------------------*/
 svymean eo if ethnic==1 
/*---------------------------------------------
 note this command is wrong because it does not define 
a subgroup of the survey
On the practical side it fails here because  you will
get a warning
stratum with only one PSU detected
Defining subsets of the survey works. It is
more forgiving to the odd lonely PSU
-------------------------------------------------*/
svymean female,by(eo)
svymean ethnic,by(eo)
svyprop eo,by(disabgrp)
/*--------------------------------------------------------------
now weighted linear models to get ses of differences
------------------------------------------------------------*/
svyregress female eo
svyregress ethnic eo
/*--------- get dummies for linear models----------*/
tab disabgrp, gen(disab)
svyregress disab1 eo
svyregress disab2 eo
svyregress disab3 eo
/*--------------------------------------------------------------
same analyses unweighted
------------------------------------------------------------*/
svyset [pweight=const]
svymean female,by(eo)
svymean ethnic,by(eo)
svyprop disabgrp,by(eo)
svyregress disab1 eo
svyregress disab2 eo
svyregress disab3 eo
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/*--------------------------------------------------------------
                table 4.6
now weighted multivariate logistic models 
------------------------------------------------------------*/
svyset [pweight=est_wt]
svylogit eo female disab2 disab3 ethnic

/*--------------------------------------------------------------
now unweighted multivariate logistic models 
------------------------------------------------------------*/
svyset [pweight=const]
svylogit eo female disab2 disab3 ethnic

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/*--------------------------------------------------------------
                table 4.7adjusted for workplace size
now weighted multivariate logistic models 
------------------------------------------------------------*/
tab nempsize, gen(numemp)
svyset [pweight=est_wt]
svylogit eo female disab2 disab3 ethnic numemp2-numemp6

/*--------------------------------------------------------------
now unweighted multivariate logistic models 
------------------------------------------------------------*/
svyset [pweight=const]
svylogit eo female disab2 disab3 ethnic numemp2-numemp6


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/*--------------------------------------------------------------
now mean of eo and by size group allowing for finite population
correction
Stata requires two things to get the finite population correct
1. A variable with the number of PSUs in the startum
2. Weights that add to the population size

first without fpc
------------------------------------------------------------*/
svyset [pweight=grosswt], strata(strata) clear(fpc)
svymean eo ,deff deft
svymean eo,  deff deft by(nempsize)
svymean eo,  deff deft by(nempsize)srssubpop
/*----------- now with fpc--------------------------------*/
svyset [pweight=grosswt] ,fpc(sampfrac) strata(strata)
svymean eo, deff deft
svymean eo,  deff deft by(nempsize)
svymean eo,  deff deft by(nempsize)srssubpop
/*----------------------------------------------------
The two analyses give the different ways that design 
effects can be defined for subgroups
The second one that compares the design with simple random
samples of the same size within subgroups is more helpful
Note that design effects are much reduced within 
subgroups. This is because the subgroups are so strogly
associated with the weighting factor here.
---------------------------------------------------------*/


/*------------------------------------------------------------
now testing the effect of a finite population correction
For this we need to make a SAS table with a record for 
each startum and a variable _rate_ with the sampling fraction
table 4.8
-----------------------------------------====---------------*/
PROC sort data=exemp4.ex4 out=rates; by strata; run;
data rates; set rates; by strata; if first.strata; _rate_=sampfrac; 
keep _rate_ strata;
run;
PROC surveymeans data=exemp4.ex4 mean stderr nobs clm rate=rates; 
weight est_wt;
var eo;
strata strata;
domain nempsize;
run;