Bookmark and Share

Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

st: polychoric matrix not positive definite

From   Tilahun <>
Subject   st: polychoric matrix not positive definite
Date   Sun, 2 Dec 2012 01:39:25 +1100

Dear all,
while attempting to perform factor analysis on ordered varaiable (with
three categories), I had to compute polychoric correlation but stata
returned the matrix is 'not positive definitive'. When computing
tetrachoric correlation on binary data, and option  - , posdef - fixes the
problem and let the correlation computed. Is there any similar option that
I can use. Please advise.

The syntax are:

The option - posdef - below fixes the problem matrix 'not positive

tetrachoric var1-var24, posdef
matrix rho = r(Rho)
factormat rho, pcf n(244)

But the syntax below returns matrix 'not positive definitive' and the
option - posdef- is not allowed here

polychoric var1-var24
matrix r=r(R)
factormat r, pcf n(244)

Your suggestion is much appreciated.

*   For searches and help try:

© Copyright 1996–2017 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   Site index