Questions tagged [mediation]
A mediator is a variable that plays an intermediate role in a causal chain. Ie, the 1st variable in the chain causes the mediator, which in turn causes the 3rd variable. Partial mediation is when the 1st variable causes the 3rd both through the mediator & directly.
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Mediation analysis with more than one predictor
I conducted a mediation analysis with 6 predictors, one mediator and one outcome variable. Now I am trying to write up the results but I am not quite sure how to structure my report...
(e.g.: write ...
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Calculating effect sizes for mediations using Process in SPSS
Can someone please help me. Last month I passed my PhD viva (yay!) with minor revisions and one of the revisions is providing effect sizes for me separate studies. For one of my studies I used the ...
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How to compare mediation models with one or two mediators?
I'm looking to compare the indirect effect sizes of two models:
IV1 -> IV2 -> DV
and
IV1 -> IV2 -> IV3 -> DV
Is there a way to do this in R?
I know how to run the first model using the ...
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Proportion mediated possible for Binary outcome, Continuous mediator?
I am running a mediation analysis on a categorical X (race/ethnicity), binary Y (disease status), and ordinal M (can be any integer 0 - 10). N-controls = 1321. Ncases = 384. I conducted this analysis ...
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Causal Mediation Analysis with treatment smoothed in the outcome stage and linear in the mediator stage
I am considering a mediation analysis that looks like the following in r:
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Mediation analysis - categorical predictor - how to set hypothetical reference?
I am running a mediation analysis on a categorical X (race/ethnicity), binary Y (disease status), and ordinal M (can be any integer 0 - 10).
I had originally calculated a percent mediated (coefficient ...
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SEM with 50% missing data (due to distribution of items over various survey ballots/waves)
I want to test a multilevel mediation (particularly, test a number of hypotheses about possible mediators of the effect of social class on Right-Wing Authoritarianism) using largely categorical ...
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ACME Significant in Mediation analysis, but not Proportion Mediated and Fitting terminated with step failure warning
I am running a series of mediation analyses in R using the mediation package and the following code:
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The percentage of the total effect that occurs through the indirect effects and direct effect
How to measure the percentage of the total effect that occurs through the indirect effects (i.e.,5.1%, 18.8%) and direct effect (i.e., 76.0%)?
For below figure,
In this figure, HFT is the independent ...
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How can I correct for using latent variables in mediation analysis?
I have 1 binary treatment and 7 latent factors as possible outcomes and would like to explore the association among them through a mediation analysis (using a structural Equation Model). Unfortunately,...
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Mediation: only c path and b path are significant?
I have done a mediation analysis in which nature contact is the independent variable, worrying is the mediator and depressive symptoms the dependent variable. I performed a mediation via PROCESS.
The ...
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How do I carry out mediation analysis when I have a continuous predictor and mediator, but a binary response?
I am having trouble getting the mediation package in R to work with what I am trying to do.
My mediator is continuous and numeric ( range is between 92-430).
My predictor is also continuous and ranges ...
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Mediation in R Package lavaan: Total effect of the IV has a different p-value than the same variable in a Multiple Regression
I am really confused with the results of my mediation analysis using lavaan. I am using one predictor and several covariates. Is there any reason why ...
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Mediation Analysis in R with two mediators in a repeated measure experiment (within-subject design)
I'm currently facing a challenge and would greatly appreciate your assistance. I'm attempting to conduct a mediation analysis with two mediators in a within-subject design exoeriment using R. Here's a ...
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Mediation analysis interpretation. negative path c but positive and significant paths for a and b
Hello I have a problem interpreting the results of my mediation analysis (Baron and Kenny)
Path a between my IV (X) and M is positive and significant.
Path b between my Mediator and DP(Y) is also ...
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Question about SNPs selection in Mendelian randomisation for mediation analysis
I recently read the paper entitled "Mendelian randomisation for mediation analysis: current methods and challenges for implementation". https://doi.org/10.1007/s10654-021-00757-1
I am still ...
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Assessing bivariate change (pre- and post-intervention) when sample size is small and there is no control group?
I have data from a randomised control trial of approximately 60 people (30 people in the intervention group, 30 in the control group). I would like to assess whether change in one variable (M) is ...
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Completely standardized indirect effect (Preacher & Kelley, 2011) in lavaan
Preacher & Kelley (2011) have proposed an effect size (i.e., completely standardized indirect effect) that quantifies the magnitude of an indirect effect. My question is whether lavaan's ...
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Mediation analysis with between & within subjects?
I have a RCT data set as follows:
IV = Group (Intervention A, Intervention B, Control)
DV = Blood biomarker, Inhibitory control, working memory
I have two research aims.
Comparing the effect of ...
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moderated mediation vs mediated moderation
I am looking for a detailed explanation of moderated mediation and mediated moderation. My basic understanding is that in moderated mediation, we have a classical mediation model with the addition of ...
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Significant index of moderated mediation but no significant interactions of moderators
I ran Hayes process Macro 8 in SPSS. In my results below, you'll see the index of moderated mediation is significant; however neither of the interactions in this model are significant. Model is below.
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Group Comparison with serial mediation
I'm trying to compare two groups for a serial mediation model. I wrote my code like in this link
to make it clearer, here is my code:
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Is a multicategorical multilevel mediation even possible?
I've tried to model a multicategorical multilevel mediation by using the logic of Hayes et al., 2014 on multicategorical mediation and an implementation of a multilevel mediation.
Here's a MWE:
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Apply custom (ANOVA-like) contrasts to all interactions in a mixed model (with a stacked dataset)
I am conducting a multilevel mediation analysis with a multicategorical X (4 levels from a 2-by-2 design) for which I want to apply custom contrasts that code two ...
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Hayes's PROCESS Multicategorical IV
I conduct an experimental research which contains 8 conditions (8 different types of fruits, 1=apple, 2=orange, 3=watermelon, 4=banana, 5=strawberry, 6=lemon, 7=pineapple, 8=grape) and use SPSS ...
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Moderated Mediation Insignificant C'
I am conducting a moderated mediation analysis using Hayes' Process Macro Model 7. I am having a significant index of moderated mediation, significant a path and b path and significant moderator X ...
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Reading tips on longitudinal mixed models and mediation
I'm a Swedish PhD student in psychology looking for advice on what to read to understand linear mixed models in a longitudinal context better. We're running a RCT with two active groups and weekly ...
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Power analysis for serial multiple mediation
Does anyone have suggested methods for running a power analysis for a serial multiple mediation model? I am running the model in SPSS with the PROCESS macro. G*power does not appear to have the ...
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Can I ignore "Control" and "Treated" from the output of the mediation package if my predictor is continuous?
I am trying to run mediation analysis to see if one continuous biological variable mediates the relationship between another continuous biological variable and a time-to-event survival outcome. I am ...
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Simple mediation analysis - significant indirect effect but no significant total or direct effect
I've done a simple mediation analysis, but not completely sure how to interpret the findings. I've found a significant (just) indirect effect, but no significant direct or total effect (see below).
I'...
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Direct effect is negative but non significant; indirect effect is positive but significant
I'm testing a simple mediation model (Model 4 by Hayes, 2018). I have what Baron and Kenny would call a 'full mediation' as results. Paths a and b are positive and highly significant (p < .001). My ...
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Moderation and Mediation model
I am trying to fit a moderation mediation model (please see the figure)
So I have a clasic mediation model and a moderator for the association between the mediator and the outcome.
I want to fit this ...
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Intercept of latent variable underlying an observed categorical Variable
In Structural Equation Modeling one approach to deal with categorical Mediators is the "underlying latent variable approach".
However using this approach e.g. with the ...
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Mediator reverses direction of causal variable. How to interpret?
I'm running a mediation in SPSS as per Baron and Kenny's guidelines (using regression). X is a dichotomous variable; M and Y are continuous.
Step 1) X-->Y (r = .07, p = .03)
Step 2) X-->M (r = .45, ...
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Double Mediation?
Can anyone help me with what this lavaan (R package) syntax is doing? I got a question: Is it correct that a kind of nested multiple mediation is tested with this ...
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Comparing path analysis models: mediation vs. (residual) covariance
I am using lavaan to run path analysis to predict PC from WA and LC. These are multi-group models. Described here is the first step (identifying best-fitting paths); it is followed by constraining ...
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How to correctly understand PROCESS model 4 for output “ Test of X by M interaction?
Perhaps some one can help me interpret some of the outputs of Hayes model 4. I designed a questionnaire that had good Cronbach and KMO scores etc. I did the PCA and have four components (factors). I ...
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How can I improve my mediation analysis to account for repeated measures (2 time points)
We are currently trying to test a mediation model with repeated measures (two time points) for a 1-1-1 level analysis.
My independent (TreatmentF), mediator (Ambivalence), and dependent variable (...
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How to perform multilevel moderated mediation analysis with {mediate}
I'm attempted to run a multilevel moderated mediation analysis in R using the mediate package. Some details on my sample:
I have an experimentally manipulated ...
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Mediation package error message with group level mediator (bug?)
I am trying to use the mediation package with multilevel data and a group level mediator. I am getting a "groups do not match between mediator and outcome models" error message.
However, I ...
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mediation in R - interpretating the absolute value of total effect, ACME, and ADE (binary exposure, mediator, and outcome)
I am a beginner of mediation analysis. In my research, exposure, mediator, and outcome are binary (0: no, 1: yes). The data is clustered by unit. I have fitted the mediate model (M ~ E) and outcome ...
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Mediation model with covariates and between and within-person mediators
I am pretty new to mediation in multilevel models.
I want to run a 2-1-1 (and maybe a 2-2-1) mediation model in R.
The dataset consists of 110 participants with three assessments per day.
covariates = ...
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Conducting a moderated multilevel mediation with more than two levels in R
I'm trying to conduct a moderated multilevel mediation model in R, but I'm still a pretty junior graduate student and I've only ever done mediation with lavaan. My outcome variable is cortisol, for ...
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Total scale is a significant mediator, but not subscales?
I am running mediation analysis where there is a significant mediating effect through the total scale for the construct I'm looking at. However, when I run a parallel mediation using the subscales in ...
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Seeking References for Mediation and SEM Best Practices
Preamble
Recently, a colleague approached me with a dataset$^1$ that they wanted to use to compare several competing mediation models using structural equation modeling (SEM). The models are simple, e....
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Mediation analysis: interpret a prop. mediated 95% upper CI > 1
I am using the R mediation package.
The output of the mediate command is as follows:
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Simple mediation analysis in PROCESS 4.2 in SPSS. The outcome variable is binary, the mediator is continuous and the IV is binary
In the first model, the IV (X) significantly predicts the mediator (M).
In the second model, the mediator significantly predicts the outcome variable (Y) but the IV (X) does not predict the outcome ...
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Question regarding control variables in a serial mediation model
i encountered questions regarding running a serial mediation model in mplus. my IV is ERS(excessive reasssurance seeking) DV is depression (DEP), my proposed two mediators are INU (internet use) and ...
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When to include a variable as a mediator or a predictor
I'm trying to understand the different models for investigating a variable of interest (mindfulness facets) against an outcome variable (anxiety). I notice that there are two possible ways for me to ...
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Mediation analysis not producing expected results, probably as consequence of multicollinearity issue
I am using the PROCESS macro to do a basic mediation analysis, with variables X,M, and Y. All are continuous. I know from theory that X and M, and M and Y respectively, should have a relationship. I ...
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