Date: Wed, 1 Jul 2009 20:47:49 -0400
Reply-To: Pete <phlarsen@YAHOO.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Pete <phlarsen@YAHOO.COM>
Subject: Need help with self-selection bias....
Longtime SAS programmer here, but a newbie to SAS procedures that correct
for self-selection bias.
I have non-random data on energy project costs that was self-reported by a
handful of companies. Some companies censored the project data by only
sending us a share of their projects and the associated costs (most likely
their best performing and most costly projects were submitted). Anyway, I
do have some information on the total number of projects that each company
undertook as well as the number of projects that were actually submitted to
I have two questions:
1) Is there a way to re-weight the sample data using acceptable bias
corrections so that I can report average project costs that may be more
indicative of the true population?
2) If I were to model project costs (dependent) against a handful of
independent variables, does it sound like the Heckman two-stage method using
the proportion of submitted projects makes the most sense? Are there better
methods out there?
Many thanks~you folks have been very helpful in the past.