# sem

1. ### How to use structural equation modeling (SEM) in prediction tasks?

Hi all, I have built a SEM model in Amos as attached image. There are five components, and one modulation factor. If I know four of the five components, can I use the model to predict the 5th component? How can I do this? Are there anything like factor score coefficient Matrix (those in...
2. ### Weighted Regression

I have a few questions in regards to setting up and running my weighted regression: Firstly, some background. I am comparing point of subjective equality (PSE) values from participants. Specifically this is the compression value of a stimulus that needs to be applied for the participant to...
3. ### Structural equation modeling - predictor measured in different group

Dear all, I am kind of stuk on the following problem: what if you would like to create a model, with several predictors. only one important predictor is measured in a different sample. The characteristics of this sample are similar. for example, you would prepare a model to describe a...
4. ### analysing cognitive rehabilitation and controlling for spontaneous recovery(SEM)

Dear all, When trying to figure out the proportion of explained variance of a cognitive rehabilitation program for stroke patients, you have to control for any progress by spontaneous recovery and diaschisis right? So if we measure progress without a cognitive rehabilitation program, you get...
5. ### Generating standardized standard errors

I am testing a structural equation model using Stata. I need to report standardized direct, indirect and total effects with associated standard errors (effects decomposition). While I can get the standardized effects, Std. Err. are only generated in relation to the unstandardized coefficients...
6. ### Structural Equation Modeling: When and why do you use Z-scores instead of Mean.

Hi. Can anyone help me answer the question why some people who do SEM use z-scores as opposed to using mean scores? (articles and books are welcomed) Thank you.
7. ### Structural Equation Modeling - Chi-Square confusion

Hi, I ran structural equation modeling in lavaan. I've run ML, MLM and MLR. The chi-square p-values are always 0.000. The data is quite nonnomal and has skewness and kurtosis. In one case the data is 250. In another research the data is 164 respondents. However, my performance fit...
8. ### [AMOS] Negative variances despite admissibility test

Hi there, I would really appreciate any help with this. In AMOS, I'm performing EFA. I have selected the Admissibility Test in the AMOS options. However, when I try to see the standardized direct effects, I still get a message saying that: "This matrix could not be estimated because there...
9. ### Easy question regarding SEM in lisrel

Hey all, I'm running a full SEM in lisrel and I'm having an issue. Below is the code. The issue is namely this: I specified Lambda Y as full and fixed, and then freed my 6 relevant parameters (1,1; 2,1; 3,2; 4,2; and 5;3). HOWEVER, Lisrel is only estimating LY(2,1) and LY(4,2) and the rest...
10. ### Nested vs non-nested model?

Hi all, I am running a confirmatory factor analysis and trying to work out if my two models are nested or not - this will be important for me to decide how I compare the models (e.g. using just the AIC and CFI statistics to compare the two models, or whether I can also use the chi-square...
11. ### Separate Error Bars in SigmaPlot12

I'm having an issue inserting asymmetric error bars into a grouped bar graph on SigmaPlot version 12. The SEM is already calculated for each "bar" on the graph and I have a column with the SEMs right next to the column with the means. The information I found for creating asymmetric error bars...
12. ### New MPLUS Fanboy - Do we Have Mplus users here?

Hello everyone, I was happy to find this forum. I am a MSc in Clinical Psychology and contrary to 99% of my colleagues I love research and doing empirical studies. I am currently doing a PhD in Nottingham (UK) and I have published few papers on behavioural addictions, mostly on Internet...
13. ### problem in gen. initial in winbugs

dear all members i have a small problem in the code below. in the last step gen initial and after press on this key i cannot get on result because the program still generate these values and i cannot get on any resutls after then i must close the program because it is not work and restart it...
14. ### Help with understanding CFA...

I hope someone can give me some pointers here... Or just point out to my muddled mind the porobably obvious things I am missing! I am running an online study where I have several statements that are worded to measure either A(say, attitude) or B(e.g. common sense), and these statements are...
15. ### Can I use Excel VBA program for AMOS?

Hey everyone! Because I need to process data before and after AMOS model running, I wanna know can I just use Excel VBA program for AMOS? If so, how can I do it? My Software Versions: 1、XP Professional SP3; 2、AMOS 22 3、Excel 2010/2007
16. ### SEM using survey data and maximum likelihood estimation - fit statistics?

I have estimated an SEM model in STATA based on survey data. Once I identify the data as survey by including sample weight and bootstrap weight variables I can no longer get fit statistics. Not even the basic X2 and associated p value. The message I receive is: model was fit with svy: prefix...
17. ### SEM with categorical variable/parceling/how to enter in AMOS?

I need to do an SEM and I'm stumped about what to do with one of my variables, which is a nominal categorical variable (previous experience in x vs. no previous experience in x). It is the only observed variable for the latent variable it is attached to. The rest of the variables in my model are...
18. ### SEM identification question

For the identification of P(Y=y|do(X=x)), one can condition on a set which has no descendants of X and d-separates all back-door paths. What would be the corresponding graphical criteria for the identification of P(Y=y|do(X=x),do(Z=z))? In particular, I have a mediation model, so I'm interested...
19. ### AMOS: 0 variance above latent variable

Hi all, I just ran my model, and it fits really well and all the parameter coefficients are strong and at least moderately high. I was confused though because the Variance reported above the latent variable is zero. The model's structure is four measured variables loading into a single latent...
20. ### Spatial Econometrics - Bias?

Dear all, I seem to be lost with the following problem in spatial econometrics: Assume the true model is a spatial error model (SEM). It is well known that using OLS for estimation is inefficient but still unbiased. Now, when I compare my OLS vs. SEM estimates in R, say, they are quite...