[R] interpreting significance of path coefficients from sem() output

From: Michael Rennie <michael.rennie_at_utoronto.ca>
Date: Tue, 06 May 2008 23:51:07 -0400

Hi there,

Quick question about the output from the sem() function in the library of the same name.

If I am getting probabilities >0.05 for some of my estimates of path coefficients, I'm assuming the interpretation here is that the coefficient is not significantly different from zero, correct? In that case, might it make sense that I should disregard path coefficients between variables where the probability is greater than 0.05? In which case, would it make further sense to remove those particular links from the specify.model() command and re-run the analysis, excluding those rows which lacked significance in the previous attempt?

Given that in just about every other example I've been able to dig up where this method is employed (including other datasets I am working with), the probabilities of the path coefficients are almost always well below 0.05, it makes me suspect that what I am observing may simply result from the fact that I'm trying to fit a path analysis among 5 variables (4 predictors, 1 criterion) based on only 18 observations, admittedly a small sample size and perhaps an overly ambitious approach to analyzing so few data.

Last, I'm convinced that I'm using the code correctly as I was able to successfully reproduce an example in Quinn and Keough (2002) before I turned the code onto my own data.

Looking forward to any thoughts or comments.

Cheers,

Mike

-- 
Michael D. Rennie
Ph.D. Candidate
University of Toronto at Mississauga
3359 Missisagua Rd. N. 
Mississauga, ON L5L 1C6
Ph: 905-828-5452 Fax: 905-828-3792
www.utm.utoronto.ca/~w3rennie

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Received on Wed 07 May 2008 - 03:54:41 GMT

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