# Tagged Questions

Structural Equation Modeling is a multivariate technique popular in social sciences. It is based on formulating a set of linear relations between variables, some of which may be latent, and estimating the whole system, typically by analyzing the covariance matrix of the observed variables.

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### Determine the degrees of freedom as well as the free parameters in an SEM using software

I need to determine both the number of free parameters to estimate and degrees of freedom of a structural equation model. I know how to calculate these values by hand. However, the model is ...
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### Are any pairs of these four structural models nested in another?

Are any pairs of these four structural models nested in another? I think the second-order single factor model is nested in the second-order two factor model (second order single factor model is when ...
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### Does the use of EFA factor scores (vs. sum/average scores) impact statistical power of subsequent analyses?

Imagine a hypothetical scenario: You have data a short survey of 9 questions that participants respond to on a continuous rating scale. You suspect that Questions 1-3 assess one particular factor (...
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### Reference needed: Who introduced the graphical representation of a SEM?

I am hoping somebody can provide a reference to the paper that provide the first graphical representation of a structural equation model (SEM) that follows the generally accepted conventions like this ...
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### Can you please help me to improve GFI in SEM analysis? [closed]

I have two unobserved variables ( A with 17 items and B with 5 items ) values which I got after adding some constraints is Notes for Model (Default model) Computation of degrees of freedom (Default ...
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### paired t-test as a simple latent change score model

UPDATE: This problem was (embarrassingly) solved by specifying the intercept in the regression equation as shown below: ...
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### Change Score Model in lavaan

UPDATE: I think I was over-complicating my problem and am struggling through a new approach as described here: paired t-test as a simple latent change score model I am still accepting the answer ...
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### Inner / outer model

i have created a SEM model and want to know while reporting which part should be treated as Structural model and which portion as and outer / measurement model . Whether i should take portion A or ...
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### How is it that Cronbach’s alpha for these 3 variables is so low, but using them to create a latent variable to predict a DV has such a high R2?

TL;DR: 3 variables score low on cronbach’s alpha but are very effective at predicting a DV when grouped as a latent variable. I am analyzing screenplays and I used software that would classify ...
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### Suggestions to improve sem results

I wish to check the assumption that physical and mental health for elders are affected by two main latent factors the physical burden (PHB) and the emotional burden (EMB). The measurement model is as ...
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### How to predict factor scores in Lavaan

In doing a CFA in Lavaan. I had to use the covariance matrix as an input because I was getting some errors with the original data (e.g., negative variances). I ...
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### Do Heywood cases render EFA/CFA solutions invalid?

If communality = 1, then we have a Heywood case, and if a communality > 1, it is known as an ultra-Heywood case. I read in a SAS manual that an ultra-Heywood case renders a factor solution invalid, ...
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### Common method variance test won't converge [closed]

I am having trouble with the common method factor technique (or CFA marker technique). I can't seem to make it work (Podsakoff, 2012). Here's my (lavaan) code: ...
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### Neural Networks Vs Structural Equation Modeling What's the Difference?

I'm studying about artificial neural networks (ANN) for the first time and I am struck by how the concepts of neural networks appear to be similar to structural equation modeling (SEM). For example, ...
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### Degrees of freedom in multiple regression thought of as a path analysis using standardized variables

I keep reading that multiple regression is "just-identified" (df = 0) when viewed as a path analysis. If I'm using unstandardized variables, I believe this. For example, with five variables—4 ...
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### CFA power analysis using existing Likert-type data with lavaan and simsem in R

To preface, this is my first foray into CFA and SEM, so please forgive me as I am likely making a number of unwitting mistakes. I am currently working on a study to validate a proposed psychometric ...
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### Selecting the best SEM model based on goodness-of-fit statistics and number of observable variables?

I am a PhD student in the field of economics. As part of my research work I am setting a SEM model. I have designed two models that present acceptable goodness-of-fit statistics respectively. ...
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### connection between standardized values in SEM output

I'm sorry if this seems a basic question. Can someone please tell me (once and for all) how standardized estimates in a SEM model are mathematically related? I don't understand how these values are ...
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### CFA indicators - means across raters

I have a CFA model that has six items, each rated by 2 raters (no rater ids). The models with residuals across raters or items was nonidentified, and the second order model was non identified. The ...
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### Getting different r-square values whe constraining the models to be equal (Testing invariance in structural model)

I compared the chi-square value from the model with all parameters allowed to be unequal across groups (e.g., parameters are set free) to the chi-square from the model where paths at time-point 1 and ...
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### Poor model fit but significant and high path coefficient values in Structural Equation Modeling

I wonder if it is possible to have a poor model fit and at the same time strong significant and high path coefficient values among the latent variables? How would be interpret this? Also, what if we ...
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### Question about the EFA model

Then, my supervisors suggested me to run EFA for the model but it ended up the items in the same group were being distributed to different groups, where the grouping of those items doesn't make sense ...
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### Moderated Correlation

I am interested in the moderation of a latent correlation. The model consists of two latent variables with three and four indicators. The latent variables are correlated and influenced by a continuous ...
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### Approach to conduct meta-analysis including data from structural equation modeling

I'm planning to write a meta-analysis on a topic in which there are both clinical trials and structural equation modeling papers. For clinical trials i can compute easily the effect size and analyze ...
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### Why does SEM not allow endogenous variables to covary with other variables?

This crossed my mind when I was reading this stata forum post, at which it is written: SEM does not allow any endogenous variable to directly covary with any other variable, only regression ...
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### Formative/composite variable as weighted additive index

I'm very new to SEM (and relatively new to stats generally). I would like to ask whether my plans generally sound reasonable before I get lost for days in the literature. The model that I try to work ...
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### Scaled vs. unscaled Chi-square statistic in CFA / GRM fit evaluation

I generally want to assess the fit of a CFA model with ordered categorical indicators (the graded response model, GRM). There are two versions of this model, the normal-ogive GRM (ordered CFA with ...
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### Can we use SEM for doing ANOVA?

I am studying the influence of gender on the attribution of motives in romantic relationships. IV= Gender; DV= Love Motive. The analysis can be done using a one-way ANOVA. I was wondering if the same ...
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### Why are implied covariance matrices in SEM supposed to be nonpositive definite?

I read at this site some tips about what to do if the implied matrix is nonpositive definite. However, it's not clear to me why this is meant to be a problem. Is the reasoning just: - The population ...
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### What is an intuitive definition/explanation of an intercept in SEM?

Some of my friends/colleagues have recently taken an interest in structural equation modelling, and I have been having to field an increasing number of questions about SEM. Often times, these ...
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### Total indirect effects: Structural equation modeling

I'm trying to calculate the total indirect effects in a structural equation model with four exogenous latent variables, four latent mediators, and one outcome variable. Mplus gives the option for the "...
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### Reporting SEM results: Standardized vs Unstandardized (LIKERT data)

When all latent constructs are measured by questions on the same likert-type scale (1-5), does it make more sense to report unstandardised coefficients rather than standardised ones? I believe this ...
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### Total R-squared: Structural Equation Model

I'm trying to calculate the total R-squared in a structural equation model. Basically, I want to compare models based on the amount of variance accounted for by the endogenous variables in general (I'...
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### Correlation residuals vs standardized residuals in SEM package in R

I've been working with SEM package in R recently that I happened to read it's manual for the standardizedResiduals. In the manual, Residuals are defined as S - C, where S is the sample covariance ...
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### Change in coefficients when another factor is included in SEM

I have a question. Let's say in an SEM model, there is a significant relationship between A and B: A-> B (beta=.400). Sometimes if I add another factor (i.e., C) ...
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### How to interpret the results when the models are constrained to be invariant in multi-group modeling

I have constrained two models to be equal, and based on the chi-square test there is no difference between the models, they are invariant. These two models contain exactly the same path coefficients; ...
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### Solving for Bias in Simultaneous Equations Model without Instruments

Suppose you have the following structural equations where wage and status are determined simultaneously and you do not have any instruments for wage or status: \$(1) \text{wage}_i = \alpha_w + \...
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### Moderating Variable in R [closed]

I've been looking for Moderating equations in R but to no avail. Can somebody tell me how to write the moderating equations in R ? assuming one perdictor, one dependent variable and one covariates. Do ...
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### Assessing fit of the CFA model with polytomous indicators (the graded response model)

I fit a graded response model using R package lavaan using function cfa. This function fits ...
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### Possible explanations for high explained variance but poor model fit AMOS

I am currently doing some research and encountered this issue in one my SEM-analysis. The full SEM model has a very high explained variance (Squared Multiple Correlations) for the explained latent ...
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### How to Simulate Random Multivariate Correlated Data and Uncorrelated Data for a given correlation coefficient and P value in R? [duplicate]

I want to simulate data with the same effect sizes and structure of my real data to perform sensitivity analysis for a pathway analysis(sem). Wesley has ...
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### Structural Equation Modelling in R with Kmenta Dataset using package sem and RAM formulation

The supply-and-demand food example of Kmenta can be specified by two simultaneous equations containing two endogenous variables Q and P and three exogenous variables D,F and Y: The Kmenta data ...
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### Can we multiply two observed items and use the composite item as single input variable for CFA/SEM analysis

Please tell if I can multiply two observed items and use the composite item as single input variable for CFA/SEM analysis. What term is used for this act of multiplying of items in SEM lingo (like ...
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### A mixed effects model for learning curves

I have data for a time it takes an animal to fall off a rod (the longer the time the better the performance), which I collected three times a day over five consecutive days for the following balanced ...
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### Path Analysis Vs Multinomial Logit

Would anyone be able to explain the logic behind using a Path Analysis over running several multinomial logits. The theoretical model I am testing has X1-3 mediating Y1. Y1 and X1 predict U1-3 (the ...
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### Path analysis and multiple mediators

I have a study with two potential mediators: M1 and M2. I obtain a main effect of my independent variable X on the dependent variable Y. Similarly, I obtain an effect of X on M1, but I do not have an ...