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Deeply Trivial
Приєднався 9 лис 2008
Conducting Mixed Effects Meta-Analysis in R
How to conduct mixed effects meta-analysis using the R metafor package.
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Відео
Conducting Meta Analysis in R
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Using R and the metafor package to conduct meta-analysis. See these previous posts for more information and code: www.deeplytrivial.com/2018/04/e-is-for-effect-sizes.html www.deeplytrivial.com/2018/04/v-is-for-meta-analysis-variance.html www.deeplytrivial.com/2018/04/w-is-for-meta-analysis-weights.html And the BMJ Open article mentioned in the video: bmjopen.bmj.com/content/6/7/e010247 Finally,...
Interpreting CFA Output
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Interpreting output of confirmatory factor analysis in R and lavaan. Here are links to the other posts referenced in the video: Confirmatory Factor Analysis: www.deeplytrivial.com/2018/04/f-is-for-confirmatory-factor-analysis.html Goodness of fit statistics - www.deeplytrivial.com/2017/04/g-is-for-goodness-of-fit.html Degrees of freedom post 1 - www.deeplytrivial.com/2017/09/statistics-sunday-w...
I'm so impressed. I've been looking at sooo many videos about cfa in r, and this is the best by a long shot. Thank you for explaining the output so well!!!!
10/10 video. many thanks!
Hi! thank you so much!! :D
Hi ! This was exactly what I was looking for. And I've searched for videos like this throughout UA-cam, in Spanish and English. Still the clearest and best explained video that I found. Thanks thanks a lot !
How do we improve model fit in CFA?
Thank you! This was a great introduction to the topic and provided a lot of food for thought. Also quite entertaining :-)
Does anyone know how to incorporate an interaction effect between two moderators in the rma function?
Thank you for you great video. For a Meta-analysis on longitudinal studies , does it make any difference in the statistical test I use? thank you for your answer
Thanks for the video! Really clear explanation!
Great explanation, really help my analysis, thank you.
Hi, Im using your video to build my RE model but I noticed it doesn't take into account the size of the sample im putting in, I added weighted =TRUE to my rma lines but i notice the sizes don't change. am i doing it wrong? do i need to set up the weights separately? thank you in advance
epic video thank you very based yes
Great video!!!! Quick question, do you think we can use the standardized factor loadings to get the weight of each variable and then use that for further graphing purposes with each person's response? Kind of multiplying each person's response with the weight? Thanks in advance!
But your assumptions is based on a normal dist but your data is skewed and categorical ? Do you have any advise/vid to handle the poly matrix to the CFA ?
Hi Sara, very helpful video. Quick question, do you abide by any cut-off factor loading guidelines for deciding whether an indicator can be regarding as loading onto a factor. I've heard that any indicator with a standardised loading of >.4 can be taken as indicative of the associated latent concept. Do you just go by the z-test significance?
Hi! how to perform esalc function in metafor when your study have more than one outcome?
Thanks for this. Very clear explanation.
Amazing! Super youtube video!
Such a great video! Thank you!
You showed the calculation for a normed chi-square, then you show another number that you indicated there was debate over using it (chi-square/ 1df). How did you calculate that number (around 25:06 minuted).
Thanks Sara, I am a noob with all this. My test statistics are 755.768, df: 424. If I divide this my normed chi square is 1.78 - not sure by what to judge now - how well/bad does my model fit? Chi Square should be around one? So, 1.78 isn't bad, but 755.768 is, or is it not?
Great question! The problem is chi-square is that it's biased to be large when samples are large. Given that SEM is a large N statistic, this means that your chi-square is coming to be significant (i.e., indicate poor model fit) the majority of the time. This is why we apply that correction using degrees of freedom, since it's supposed to counteract that large N. The problem, though, is that no one seems to agree on what your normed chi-square should be less than, with some saying 1, some saying larger values like 5. I usually use 3.841, which is the chi-square critical value for df = 1. Depending on who you talk to, that will either be too conservative, too lenient, or just right. But what people DO seem to agree on is the chi-square shouldn't be the deciding factor on whether your model fits well. Your other fit statistics, like RMSEA, CFI, TLI, etc., give you much better info. So if those indicators show good model fit, you're probably okay.
@@DeeplyTrivial Thanks! I have N = 220 and about 30 variables. So my sample is not large. I was looking at different models, with 5 to 8 factors and normed chi-square ranges from1.5 to 1.8. Differences seem to be minor between all different models. Therefore, I am thinking I should look at the questions and what factors make the most sense. One more issue, I have very weak correlations among the variables, and the sample comes from a very diverse population (Likert Data). I wonder if CFA makes even sense for that matter. Thank you so much Sara.
Great video. Very nice way of explaining stuff. I had R and my CFA open and understand everything now :)
Thank you! This is super helpful!!!
Dear Sara, Thank you so much for posting this. You explain everything very clearly. Absolutely fantastic :)
Dear Sara, Thanks for this. Coming across these videos and your blog has been a life saver! Keith
Hi Sara, Thank you for a very clear and informative explanation of the methods! I love this! I also love your off-topic remarks about reviewer 2 - you go girl! I am going to cite the mentioned BMJ paper in my thesis and, hopefully (one day), publication! Is there any chance you could do moderator analysis (mixed-effects model) using argument *mods* ?
Thanks Sara! This is so clear. One question: when reporting the factor loadings from a CFA, do you report the estimates, or the standardized estimates?
Glad to hear it! I usually try to report both in a table, but if I had to choose one over the other, I'd probably go with standardized estimates. I find them easier to interpret, especially if different variables in the model use different metrics.
What are the premise for this analysis? If you provide what you already have before starting analysis, that would be very helpful.
This is impressive!! What is the difference between mixed effect MA and meta regression ?
Thanks Sara, it helped a lot :)!
And two-category data/binary data would be used by MetaBin?Here,is the data survival data?.Thanks a lot
Actually helped with my analysis. Thank you.
This was a really fantastic video! Is there any chance a video for conducting a mixed effects model meta-analysis is coming soon?
Yes, working on it now - look for it soon!
@@DeeplyTrivial Could you explain why REML and DL are the preferred methods in Fixed, Random and Mixed Effect Models?