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Date:         Thu, 23 Feb 2012 11:35:24 -0500
Reply-To:     Gene Maguin <>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Gene Maguin <>
Subject:      Re: guidance on assigning cases to participant and control groups
In-Reply-To:  <>
Content-Type: multipart/alternative;


Maybe I'm not understanding something but why have you rejected random assignment of owners to condition?

Gene Maguin

From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of Martha Hewett Sent: Thursday, February 23, 2012 11:14 AM To: SPSSX-L@LISTSERV.UGA.EDU Subject: guidance on assigning cases to participant and control groups

I'm involved with a project that is recruiting 100 to 200 owners of multifamily properties, with 1 to 10 properties each (average 5), for an energy efficiency project. Because the project's effectiveness depends in significant part on influencing the owners, we need to assign all of any given owner's properties to either participant or control status. Beyond the owners, however, there are many property-specific factors that may affect savings, such as the age of the buildings, number of units, type of heating equipment, etc. Obviously there will not be enough owners or properties to match the participant and control groups on all of these dimensions.

So my question is, when you have a large number of more or less independent (but possibly somewhat correlated) dimensions that may affect outcomes relative to the size of your sample, what is the best way to assign cases to participant or control status? What additional considerations are introduced by the fact that I have to assign participant/control status by owner but need to consider other factors by property?

If someone can point me to a suitable methodology, I'm sure I can figure out how to apply it.

And yes, I agree, wouldn't it be great if n could be bigger?

Martha Hewett

Director of Research | 612.335.5865

Center for Energy and Environment

212 Third Avenue North, Suite 560 | Minneapolis, MN 55401

(cell) 612.839.2358 | (fax) 612.335.5888 | <>


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