[R] please help with estimation of true correlations and reliabilities

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From: Jens Oehlschlägel (joehl@gmx.de)
Date: Thu 13 May 2004 - 19:06:08 EST


Message-id: <2326.1084439168@www8.gmx.net>


Can someone point me to literature and/or R software to solve the following
problem:

Assume n true scores t measured as x with uncorrelated errors e , i.e.
x = t + e
and assume each true score to a have a certain amount of correlation with
some of the other true scores.

The correlation matrix cx of x will have its off-diagonal entries reduced by
measurement error compared to the true correlation matrix ct of t, however
the diagonal entries remain without attenuation. Consequently the
correlation matrix of observed variables has different things on- and
off-diagonal.

I would like to estimate
1) the true correlation matrix ct
2) the measurement reliabilities rxx, i.e. the correlation of a score with
itself attenuated by its measurement error (as if we had two measurements of
the same score).
but I don't have predefined asumptions about structure in the variable set
as I guess would be needed for SEM.

Is R software available to do this?

Best regards

Jens Oehlschlägel

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