Talk:Structural equation modeling/Archive 1

Archive 1

"SEM has several important advantages ..."

"SEM allows for multiple dependent variable, whereas OLS regressions allows only a single dependent variable." I would say no: SEM is a model where as OLS is an estimation technique. OLS can be used for SEM.

"SEM allows simultaneous tests of multiple groups". I do not understand this: OLS can be used for multivariate regression analysis... In this type of model/analysis there are several response/dependent variables.

"SEM accounts for measurement error, whereas OLS regression assumes perfect measurement." In multivariate regression analysis you have Y=XB+U, and the Y is assumed to be confounded with measurement error (the U's).

- fnielsen 11:24, 10 March 2006 (UTC)

To fnielsen: Most of the notes you made are SEM jargon.

OLS cannot be used for SEM because of the measurement error. Or rather the class of SEMs to which OLS is applicable is very narrow (recursive/trinagluar models where all variables are observed; those are not very interesting).

Multiple groups means that you might have different parameters for different subpopulations. In OLS, you would model that through interactions. In SEM, however, there are way more parameters than just slopes, so you may have say the same loadings, but different measurement error variances between males and females. Multiple group comparisons are then based on nested hypotheses where you allow some of the model parameters vary between groups.

OLS assumes X's are fixed. Typically, that's too much a luxury to assume with SEM where most of the observed variables are truly random variables and contain measurement error.

GLM means generalized linear model to most statisticians; using it for general linear model is rather awkward, I'd say.

- Stas Kolenikov 16 March 2006

SAS is the main perpetrator of this misunderstanding (PROC GLM). Btyner 15:15, 16 April 2006 (UTC)

Category

Should this page have another category? I thought I remembered reading that a page should have at least two categories but cannot find the policy at the moment. Any suggestions? --Kenneth M Burke 01:39, 2 August 2007 (UTC)

POV

The introduction I think might have some problems with point of view, i.e. that SEM is confirmatory rather than exploratory. Not to mention, I think it is plagiarized from another website. Not being an expert and where parts of the introduction does cite sources, I did not put a POV template on the page. This being said, maybe a more textbook language common to mathematics and research methods would be better than the "confirmatory" and "exploratory," which sounds like its from a bad sci-fi movie that didn't do its homework. Just casual thoughts and suggestions. --Kenneth M Burke 01:32, 20 August 2007 (UTC)

Well, after doing my own homework, that's what they call it. But, the amount of information that one can find on both exploratory and confirmatory SEM I think certainly shows problems with POV in the article. --Kenneth M Burke 01:43, 20 August 2007 (UTC)

I've come to strongly believe that the information on SEM as primarily confirmatory is biased. Even the most basic of introductory texts note that it is not exclusively confirmatory (Kline, 2005, p. 9, New York: Guilford Press, Principles and practice of Structural Equation Modeling). We need remember that SEM is not a single method, that there are many means and methods for SEM. --Kenneth M Burke 18:00, 28 October 2007 (UTC)

SEM- Censored data, categorical data, and Likert scale

Hi,
Though not an expert in SEM, I have developed an interest in the subject and The SEM softwares. I will recommend that,That the article include more information on censured Data and Categorical data.

The main contention is when do we consider a Likert scale to be continous? Can we Indexes in SEM? Wadson12 13:58, 9 November 2007 (UTC)

independent variables in structurla mnodels

I am not sure if the independent cvariable in a structutural model could be an observable variable (no construct). I am very grateful if anyone clarify me that point Thanks a lot —Preceding unsigned comment added by 83.40.89.47 (talk) 11:56, 31 December 2008 (UTC)

TETRAD: External links embedded in the text

I am disturbed by the reference to the TETRAD project, which contains a link to a web site outside of wiki. Shouldn't external links go to the bottom of the article? And if each one of us inserted free advertising for our own project into wiki articles, what would become of wiki? 193.255.135.1 (talk) 13:17, 7 April 2010 (UTC)

Goodness of Fit Section

When describing Chi Square, RMSEA, etc., it would be helpful to cite sources to say that if it is over .1, for example, the model does not fit well. It would be helpful to have the seminal work that is always cited in academic articles. —Preceding unsigned comment added by 72.253.236.36 (talk) 09:35, 25 February 2011 (UTC)

advantages and disadvantages of using SEM

i'm a college student now and i'm doing my final project. It is a reseach which is using SEm. Can anybody tell me what is the advantages and disadvantages of using SEM? How about comparison of SEM and another multivariat methods? thx before..

kind regard

donny

Monday, 3 November 2008

SEM is quite advanced. In comparison to PLS, SEM can caluculate specific goodness-of-fit indices. That is, you know how good your model fits the data. The main disadvantage of SEM is that you need a quite large sample (typically much larger than 300). PLS works fine with samples <200. And you must be aware that SEM wouldn't work correctly if you specify a model with formative rather than reflective measurement scales. In practice, his is often neglected, which often leads to nonsense findings. PLS can estimate both formative and reflective models. But in general, SEM is a fine method if you want to estimate models which build on multi-item measurement scales. 85.179.138.248 (talk) 05:45, 8 January 2012 (UTC)

History is missing Joreskog

A piece on SEM without mentioning Karl Jöreskog? Very very strange!

As much as I respect Pearl's work, he cannot in my opinion be seen as "the person to formalize SEM" as this article claims. His work certainly has bearing on SEM but many went before him... — Preceding unsigned comment added by 137.56.58.180 (talk) 13:58, 14 January 2013 (UTC)

No Equations?

The Stuctural Equation Modelling page has no equations. So what exactly ARE these "structural equations" then? Can we see them/write them down? Or does the work "equation" in SEM not mean equation in the normal mathematical sense? — Preceding unsigned comment added by 31.221.13.140 (talk) 09:14, 13 March 2013 (UTC)

SEM-specific software

The section should contain notable entries only, and no links to their own websites. --Ronz (talk) 03:13, 8 April 2013 (UTC)

Please show me this in the WP guidelines.

The WP:Notability criterion applies to the main topic of an article, not to WP:references. Referencing an official web page that supports a claim is usually fine. The software R is extremely notible as it is widely used in statistics and data analysis. A reader of this article is reasonably likely to be an R user and would be interested in the various packages. Those packages are provided by various people, not including me.

Perhaps there needs to be a new page R packages to guide readers to the many contributed packages and task views. Tayste (edits) 19:11, 9 April 2013 (UTC)

I didn't mention WP:N, so let's not get off track.

WP:SOAP and WP:NPOV.

Trying to make it a stand-alone article would make it a WP:CFORK. --Ronz (talk) 20:37, 9 April 2013 (UTC)

Please show me which WP guideline states that the "section should contain notable entries only". It is your use of the word notable in this context that I am querying. Tayste (edits) 00:18, 10 April 2013 (UTC)

And which WP guideline forbids "links to their own websites", especially when I formatted them as references rather than direct links? Tayste (edits) 00:22, 10 April 2013 (UTC)

I didn't claim the policies contain those exact quotes, so let's not get off track.

I use the word "notable" to indicate two things: First, if an entry has it's own article, and that article meets WP:N, then it would likely to be fine. The entries' articles also provide a proper location for any official website that might exist per WP:ELOFFICIAL.

Second, if an entry can be shown to be worth noting with sources that are both independent and reliable that might not be enough to justify it's own article but demonstrates that it would be due weight to include in this article, then that would probably work as well.

Finally, we only add links in the body of an article as references per WP:EL. --Ronz (talk) 04:19, 10 April 2013 (UTC)

While you're on this hobby horse, you might like to stop by other pages with similar sections, e.g. Principal component analysis, Student's t-test, Generalized estimating equation... Tayste (edits) 00:30, 10 April 2013 (UTC)

Thanks for pointing them out. --Ronz (talk) 04:19, 10 April 2013 (UTC)

Planning to work on this page

Hi everyone, I just finished a grad course on SEM and plan to try to improve several aspects of this currently C-class article - I've got lots of citations handy from my course readings, so I figure it's a good opportunity to "give back." The "sample size" section and the fit indices seem to need citations in particular. Let me know if you were also planning to work on this page in the next few weeks! Happy to collaborate. Sharp-shinned.hawk (talk) 15:47, 24 January 2015 (UTC)

History

Much of this article is paraphrased from Westland, J.C. (2015) Structural Equation Modeling: From Paths to Networks, New York: Springer, 2015, though in its brevity, the article omits some significant information, and purposely distorts other information.J.christopherwestland (talk) 17:01, 28 November 2015 (UTC)

I have modified the content to accurately reflect both the history presented in Westland, J.C. (2015) as well as to correct misstatements concerning sample size. I have put in references to Westland (2010) that describe sample size calculations for these methods.J.christopherwestland (talk) 17:01, 28 November 2015 (UTC)

Today, SEM is a general term used to describe either of two computer based statistical fit software packages: PLS-PA and LISREL/AMOS software. Sewall Wright developed Path Analysis, which is different; Trygve Haavelmo helped develop systems of regression approaches, and derided PLS-PA and LISREL as unscientific. Simon and Pearl made no contributions to these software packages.

I just finished a graduate course devoted to SEM and had to read several textbooks and over 50 articles about the technique - you are right that SEM is a general term, but authors repeatedly describe it as a class of statistical techniques, not specifically "software packages," although this article does need to keep info about the software; it is important. Also, I think MPLUS needs to be mentioned in the family of statistical software that can be used. I'll plan to work on the overall definition based on my course readings, and may break out a section on software. Sharp-shinned.hawk (talk) 13:53, 24 January 2015 (UTC)

I'm happy to listen to any discussion of 'statistical algorithms' but I have studied the code (I was one of Claes Fornell's students, and had access to the original PLS-PA and LISREL source code) and there is no consistency in the application of any algorithms. The software depends on iterative search and varies from package to package. J.christopherwestland (talk) 17:01, 28 November 2015 (UTC)

SEM vs Graphical Models, Bayesian networks

Could someone please explain the difference?

SEM is a graphical model where the distributions are all assumed to be normal (usually, though there are extensions). Conditional independence (or local dependence) is expressed by the path diagram/effect matrix. More explanation is in the J. Pearl book (2000). —Preceding unsigned comment added by 80.174.156.18 (talk) 14:57, 21 September 2008 (UTC)

This assertion is silly ... SEM is a general term for different algorithms. Wright's 'path model' graphics are used to describe the models, but each has it's own algorithms. Bayesian networks are a different animal altogether -- there is a reasonably good article in wikipedia on that alreadyJ.christopherwestland (talk) 17:04, 28 November 2015 (UTC)

contributions

Hi, I think the article is excellent and am disturbed by the clean-up indicators at the beginning that make it appear that there are serious problems. Nothing is perfect; however I was greatly informed by the clear writing, which I felt was not too technical and perfectly understandable. --Littleelf (talk) 11:31, 31 March 2008 (UTC)

The article definitely needs cleanup and fact checking. Many of the assertions are untrue or inconsistent with each other, and the overall presentation is sloppy. The relationship of these approaches to the broader body of statistical methods (including links to other Wikipedia articles) needs to be added before this article is fully acceptable. J.christopherwestland (talk) 17:13, 28 November 2015 (UTC)

Hi, I would like to invite authors to contribute articles to this entry. Some things that can be included are:

1. Lesson plans for teaching SEM 2. List of good books on SEM 3. Key, "must read" articles

Why would a Wikipedia article contain 'lesson plans' and 'good books' and 'must read' articles ... these are all highly subjective and the suggestion seems to me to be an abuse of WikipediaJ.christopherwestland (talk) 17:13, 28 November 2015 (UTC)

Hello,

It seems that emphasizing the difference between linear multiple regression and SEM is important for this article. Does anybody know more about this? To be frankly, I cannot see any urgent needs to state that y_i is determined by y_0,1,2, ..., n (except for i) in SEM. What can be the situations that can be described better with SEM than with linear regression?

Please see Westland (2015) which describes how SEM path analysis models (with latent variables) can be operationalized in systems of regression equations J.christopherwestland (talk) 17:13, 28 November 2015 (UTC)

I'll be working on this page at my leisure time, if any, as this is my major research topic. What would be the best way to incorporate path diagrams into Wikipedia? I can do matrices with MathML, or whatever interface Wikipedia has for math, but the path diagrams would obviously have to go as graphics files.

Stas Kolenikov

Hi

The 'historical' introduction right now is only focused on econometrics. But it might be more clarifying to state that SEM is a combination of factor analysis (Thurstone) and path analysis (Wright). This should ring some bells for most people coming to this page. As far as I know, Joreskog, not Pearl, was the first to formally combine the two in 1970 [[1]].

It was Hermann Wold, in the development of computational methods for PCA and canonical correlations in the 1930s, who originated these extensions of Wright's path analysis J.christopherwestland (talk) 17:13, 28 November 2015 (UTC)

best, daniel (sorry for not logging in, next time I will) —Preceding unsigned comment added by 80.174.156.18 (talk) 14:45, 21 September 2008 (UTC)

I too was surprised to see no mention of Joreskog, Sorbom, Muthen or other key figures in SEM. 131.96.47.13 (talk) 14:40, 13 October 2009 (UTC)

Most of the historical material was paraphrased from Westland (2015), and was done sloppily (thus the omission of key figures) J.christopherwestland (talk) 17:13, 28 November 2015 (UTC)