Date:         Mon, 26 Sep 2005 17:02:15 -0700
Reply-To:     "Seumas P. Rogan" <sprogan@email.arizona.edu>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         "Seumas P. Rogan" <sprogan@email.arizona.edu>
Subject:      How to compare survey data to census
Content-Type: text/plain; charset="us-ascii"

Hi all,

I want to compare the distribution of certain variables from my survey
sample with census data for the same population, but I'm not sure which test
to use.
I have, for example, a 4-row by 2-column table where one column represents
counts from the census, the second column represents counts from my sample.
The four rows represent counts in 4 categories of household size. In the
following example, I get a Pearson Chi^2 of 8.013, df=3, p=0.046, though the
maximum difference in any cell between the census and my survey for each
size category is 1.1%.

DATA LIST /SOURCE 1  SIZECAT 3  COUNT 5-10.
BEGIN DATA
1 1 38857
1 2 64551
1 3 76809
1 4 4891
2 1 328
2 2 546
2 3 627
2 4 23
END DATA.
FORMATS SOURCE SIZECAT COUNT (F6).
VALUE LABELS SOURCE 1 "CENSUS" 2 "SURVEY".
WEIGHT BY COUNT.
CROSSTABS
  /TABLES=SIZECAT BY SOURCE
  /FORMAT= AVALUE TABLES
  /STATISTIC=CHISQ
  /CELLS= COUNT COLUMN
  /COUNT ROUND CELL .

Does anyone have any suggestions or advice here? Are there any heuristics or
guidance regarding how to compare surveys with 'truth' and how different
distributions must be to be 'different'?

Thanks for any help!


SR

sprogan@email.arizona.edu