Date: Mon, 31 Jul 2006 15:37:27 -0400
Reply-To: Stephen Brand <email@example.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Stephen Brand <firstname.lastname@example.org>
Subject: Re: Cronbach's Alpha if item deleted
Content-Type: text/plain; charset="US-ASCII"
If the increment in alpha is very small, you might want to use this
information to shorten your measure in future studies. The benefit of
cutting the item is not so much that alpha goes up but that you make the
survey go faster for the participants without losing information.
Stephen Brand, Ph.D.
Associate Professor (Research)
NCPE-SP, University of Rhode Island
Kingston, Rhode Island
From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of
Sent: Monday, July 31, 2006 11:00 AM
Subject: Cronbach's Alpha if item deleted
I am using Cronbach's alpha to test the reliability of an index I want
create. I am getting values of around 0.9 which I am very happy with,
sometimes SPSS says that alpha would be improved if I removed one of the
variables. What sort of cut-off point should I use for this? Some of the
improvements are very small (e.g. 0.002). Is it worth removing these
I have several datasets each asking a range of questions which overlap
quite a lot. In one case, even though an improvement is very small, it
would make an improvement to remove it in every dataset which uses it.
Would this mean I should remove it even if just looking at one dataset I