Re: Random sample matched on variables

Posted by Bruce Weaver on Nov 11, 2012; 1:55pm
URL: http://spssx-discussion.165.s1.nabble.com/Random-sample-matched-on-variables-tp5716152p5716153.html

From what you've said, it sounds as if N=65 for control versus 25-30 for the other two groups.  That is not what I would describe as a large discrepancy in sample sizes.  

What type of study design is it? (E.g., see http://www.med.uottawa.ca/sim/data/Study_Designs_e.htm.)  

What kinds of outcome (dependent) variables do you have, and what types of models are you using?  

Koen N wrote

Dear more experienced than me SPSS users,

I'm currently working on a research project in which I've hit a wall. I have three groups which I want to compare on a number of analysis. One of these groups is much too large compared to the other groups. This much too large group is a control group. The other two groups are comprised of a rare demographic. As of such, I want to drop my control group of 65 down to 25-30 while matching them on certain demographic variables (namely age, IQ and education). The other two groups don't differ significantly from one another on the mean of these variables. My control group does differ sognificantly. I want my control group sample to be within the same range of the means of my other two groups.

Obviously (otherwise I wouldn't be posting), I am completely lost as to how to do this. I assume I'll be using the syntax, but I am unsure what commands I should be using. I've searched around and found some similar cases as mine, except they wanted to take a random sample based on propensity scores (which I don't believe works for me) or they wanted to take a sample out of two groups (while I want a sample out of one).

If anyone could assist me, I would be very grateful. Thanks for your time!