Date: Thu, 23 Feb 2012 07:02:41 -0700
Reply-To: Jon K Peck <peck@us.ibm.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Jon K Peck <peck@us.ibm.com>
Subject: Re: Fwd: What is the best approach for my research?
In-Reply-To: <CAFmRK8esH-x6r8ZSo1V_kjuJTxzKG7_-MwHtVLwnd_2LA2URBg@mail.gmail.com>
Content-Type: multipart/alternative;
Rasch models are available in Statistics via several extension commands.
STATS IRM fits a 3-parameter item response model
STATS GRM fits a graded response model to ordinal data
SPSSINC RASCH estimates an item response model
All of these can be downloaded from the SPSS Community website (
www.ibm.com/developerworks/spssdevcentral) The R Essentials, also
available from that site, is a prerequisite.
Jon Peck (no "h") aka Kim
Senior Software Engineer, IBM
peck@us.ibm.com
new phone: 720-342-5621
From: Benjamin Spivak <benjamin.spivak@monash.edu>
To: SPSSX-L@listserv.uga.edu
Date: 02/23/2012 06:20 AM
Subject: [SPSSX-L] Fwd: What is the best approach for my research?
Sent by: "SPSSX(r) Discussion" <SPSSX-L@listserv.uga.edu>
Hi Ryan,
Thank you very much, I will look at Rasch models and attempt to apply it
to my work. Could I trouble you with another question.
Say, I do find that there is a uni-dimensional construct underlying
comprehension. How could this assist me to look for differences between
conditions?
Regards,
Ben
On 23 February 2012 23:41, R B <ryan.andrew.black@gmail.com> wrote:
Benjamin,
The first thing I would consider would be whether there is an underlying
unidimensional construct underlying comprehension. You could fit a Rasch
model via Winsteps, which allows for items with varying response options.
Ryan
On Thu, Feb 23, 2012 at 1:14 AM, Benjamin Spivak <
benjamin.spivak@monash.edu> wrote:
Dear List,
Please help I am stuck. I am performing some jury research with some very
strange result and I want to find the ideal statistical model to fit my
data.
My study. Essentially a 2x3 jury simulation study measuring comprehension
of law. I also have over 18 DV's (questions) for comprehension. I have
considered condensing the questions into one variable. But Cronbach's
alpha is quite low for any combination of questions that I can relate to
one construct.
Distribution is extremely non-normal and there is a heterogeneity of
variance between groups. Also, because the jury study uses deliberating
groups I have violated the assumption of independence.
Considering all this, I am having real trouble determining what the best
approach for analysis would be. I have tried multi-level linear modelling,
but I get results that I cannot make sense of.
I am at my wits end. If somebody could help, I would be in their debt.
Regards,
Ben.
I would like to analyze individual jury data, but clearly my model
violates the assumption of independence. So I have to account for this.
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