[Rasch] current issues of research in psychometrics?

Andrew Kyngdon akyngdon at lexile.com
Mon May 7 10:43:30 EST 2012


Trevor,



I believe the notion of arbitrary zero points was introduced because of the
limitations of pencil and paper based tests, not because “absolute” zero
points for cognitive abilities are theoretically implausible. Given the
psychometric focus on test calibration rather than the development of
behavioural theory, this notion has persisted.



Zero cognitive development is quite fine for me. When after conception
might that be?



I am not sure if an absolute zero magnitude of a cognitive ability is
necessarily restricted to a single point in time. Taking the Lexile
Framework for example, where individual differences in reading ability are
caused by individual differences in verbal working memory capacity and
vocabulary, a newborn human infant without a vocabulary would plausibly
have no reading ability (as would have had the foetus/embryo). That zero
magnitude likely persists for some time until the necessary cognitive
development occurs. Trees and rocks, of course, always have zero reading
ability.



Having said that, a person’s assessed reading ability is likely to be their
amount of cognitive growth in reading at that particular time of
assessment. Gary Williamson’s work with Lexiles and growth is relevant
here; and I know Steve Humphry has explored this idea in more general terms.



I dare say that if you look around the world, Syria might be a good start,
it is cognizable there are cases below Julia's zero.



Maybe, but it might be stretching it… ;)



Andrew



*From:* rasch-bounces at acer.edu.au [mailto:rasch-bounces at acer.edu.au] *On
Behalf Of *Bond, Trevor
*Sent:* Saturday, 5 May 2012 10:26 AM
*To:* rasch at acer.edu.au
*Cc:* rasch at acer.edu.au
*Subject:* Re: [Rasch] current issues of research in psychometrics?



A nice point, Andrew. And a sad one. But it light of your other erudite
remarks, it makes light of you important remarks about the zero point. I
dare say that if you look around the world, Syria might be a good start, it
is cognizable there are cases below Julia's zero.

Zero cognitive development is quite fine for me. When after conception
might that be? Piaget saw modified reflexes as the first signs of
intelligence. Others say animals do that, so that doesn't count.

Best

T

Sent from 007's iPad


On 03/05/2012, at 4:45 PM, "Andrew Kyngdon" <akyngdon at lexile.com> wrote:

A human example of a true zero point is Julia Gillard, the Prime Minister
of Australia. She has proven to everyone that she has zero ability to
govern a country. J
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