[Rasch] formative v. reflective measures in assessment research

Michael Lamport Commons commons at tiac.net
Sun Oct 27 07:05:58 EST 2013


Please give examples

On 10/26/2013 11:32 AM, Luis Carlos Orozco wrote:
> There is a recent article in Frontiers in Psychology august 2013 
> volume 4 by Stenner, Fisher, Stone , Burdick  "Causal Rasch models". 
> That could help you.
>
> Luis C. Orozco V. MD MSc
> Profesor Asociado
> Escuela de Enfermería
> Universidad Industrial de Santander
> Colombia
>
>
>
> 2013/10/26 Donald Bacon <dbacon at du.edu <mailto:dbacon at du.edu>>
>
>     Hi all --
>
>     To offer more explanation on my reflective v. formative question,
>     in reflective measurement models, the construct/latent trait
>     causes the measures/indicators/items, whereas in formative models,
>     the measures cause the latent trait.  Jarvis, MacKenzie and
>     Podsakoff (J Consumer Research, 2003) offer a thorough description
>     of this difference.  They cite Bollen and Lennox (Psych Bull,
>     1991) as identifying the same distinction, except that Bollen and
>     Lennox call reflective indicators 'effects indicators' in a
>     principal component model, and formative indicators 'causal
>     indicators' in a composite latent construct model.
>
>     Jarvis et al. cite a formative example from Crosby and Stephens
>     (1987) that I will paraphrase here.  In measuring the construct
>     "personal contact with life insurance agents", suppose the
>     following measures are used:
>
>     I was contacted by my agent to make changes in my policy
>
>     I was contacted by my agent to sell me more life insurance
>
>     I was contacted by my agent to describe new insurance offerings
>
>     I was contacted by my agent to keep my policy in place
>
>     In these items, the agent would not suggest keeping the policy and
>     changing the policy, so the inter-item correlations here should be
>     low or perhaps even negative, yet all of these statements indicate
>     personal contact.  Internal consistency is not necessary for
>     formative measures; to assess the quality of formative measures we
>     need to look at criterion-related validity.  Thus, formative
>     models are a bit more like regression models, where the many
>     independent variables are assumed to have no error and may have
>     low intercorrrelations but the one dependent variable does have error.
>
>     Jarvis et al. go on to report how measurement models have often
>     been misspecified, even in top marketing journals, as formative
>     measures have been treated as reflective and vice versa.  They
>     show how such misspecification can bias structural path estimates.
>
>     Getting back to Rasch measurement, it seems to me that Rasch
>     assumes a reflective/effects/principal components model. However,
>     Rasch may occasionally be misapplied to formative indicators.  In
>     the latter case, model fit and internal consistency would probably
>     be low, but this is due mainly to fundamental model
>     misspecification.  Or can Rasch be used with formative indicators?
>
>     Has this type of model misspecification been discussed in the
>     Rasch literature?  More specifically, are all tests of ability or
>     knowledge generally reflective models?  Is there a good cite that
>     someone can point me too?
>
>     Thanks for any insights you may be able to provide.
>
>     Don
>
>     *From:*rasch-bounces at acer.edu.au
>     <mailto:rasch-bounces at acer.edu.au>
>     [mailto:rasch-bounces at acer.edu.au
>     <mailto:rasch-bounces at acer.edu.au>] *On Behalf Of *Bond, Trevor
>     *Sent:* Saturday, October 26, 2013 1:17 AM
>     *To:* rasch at acer.edu.au <mailto:rasch at acer.edu.au>
>     *Subject:* Re: [Rasch] formative v. reflective measures in
>     assessment research
>
>     Dear Donald,
>
>     Perhaps you could share what you mean by formative and reflective,
>     so we might be able better to answer your question.
>
>     Collegially
>
>     TGB
>
>     *From: *Donald Bacon <dbacon at du.edu <mailto:dbacon at du.edu>>
>     *Reply-To: *"rasch at acer.edu.au <mailto:rasch at acer.edu.au>"
>     <rasch at acer.edu.au <mailto:rasch at acer.edu.au>>
>     *Date: *Saturday, 26 October 2013 3:57 AM
>     *To: *"rasch at acer.edu.au <mailto:rasch at acer.edu.au>"
>     <rasch at acer.edu.au <mailto:rasch at acer.edu.au>>
>     *Subject: *[Rasch] formative v. reflective measures in assessment
>     research
>
>     Hi all --
>
>        The Rasch model assumes that each measure in a scale reflects
>     the same underlying trait, and so it seems that a reflective
>     measurement model is appropriate, and internal consistency is a
>     desirable quality.  But what about the case of a long
>     comprehensive exam, such as one we might use for assessment.  In
>     my experience, these exams often behave as if they were close to
>     unidimensional, even though many different learning outcomes are
>     captured.  If well designed, these tests often exhibit high
>     internal consistency.  Because the models fit well, I've always
>     thought of the measures as reflective, but perhaps my theory is
>     wrong even though the fit is good; maybe the measures are
>     formative.  Is there any way to use the Rasch model with formative
>     indicators?
>
>     Thanks for any insights you might have --
>
>     Don
>
>     Donald R. Bacon, Ph.D.
>
>     Professor of Marketing
>
>     Editor, Journal of Marketing Education
>
>     Daniels College of Business
>
>     University of Denver
>
>
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-- 
My Best,

Michael Lamport Commons, Ph.D.
Assistant Clinical Professor

Department of Psychiatry
Beth Israel Deaconess Medical Center
Harvard Medical School
234 Huron Avenue
Cambridge, MA 02138-1328

Telephone  (617) 497-5270
Facsimile   (617) 491-5270
Cellular      (617) 320 0896
Commons at tiac.net
http://dareassociation.org/
Skype: MichaelLCommons


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