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 many exposure variables

Does it make statistical/modelling sense if I would like to have a mediation analysis with many exposure variables (e.g. X1 and X2) but one mediator (M), where my main interest is about the causal ...
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8 views

Total effects read the same in mediation analyses

I was trying to conduct a mediation analysis to assess the effects of three different mediators between the IV and the DV. However, despite the a paths, b paths and c' paths being different for all of ...
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16 views

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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2 views

Preacher & Hayes mediation 'model summary for dv model'

I have a (probably very stupid) question. I am doing a preacher & hayes mediation analysis on my data, but was wondering what the values for 'model summary for dv model' mean. I tried google but ...
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19 views

Power analysis for regression with multiple mediators using bootstrapping (PROCESS)

I am currently trying to help a friend of mine with some statistical analyses for her master project, and she has come up with this question, which might be of interest to others (wel'll see) and to ...
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20 views

Interpret nonsignificant mediation linear regression analysis

Undergraduate psychology student here with a probably easy question. I tested a mediation hypothesis with SPSS using linear regression. I did not find this hypothesized mediation, but I still have ...
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1answer
40 views

How can I test possible reasons for the relationship between income and handedness?

For a project, I am trying to determine what accounts for the difference in income between left handed people and right handed people. (For example, whether it is only among males, or only in a ...
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24 views

Interpretation of Bootstrapping's Result

i am currently doing my final thesis and in need for help. I am using Bootstrapping to identify the indirect relationship of celebrity endorsement (CE) to purchase intention (PI) with brand image (BI) ...
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6 views

indirect effect role in mediation

there are 4 conditions for the significance of mediation.1:significance of (X → Y),2:significance of(X → M) 3: significance of(M|X → Y) If one of these is not fulfilled,does it means insignificance ...
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what does Direct effect significance and insignificance means in mediation

There are 4 conditions for the significance of mediation: Significance of (X → Y), Significance of(X → M) Significance of(M|X → Y) , Insignificance of (X|M → Y). Does it mean partial ...
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26 views

What's the difference between including a variable as a mediator in a mediation analysis, and including a variable as a covariate in ANCOVA?

I understand that ANCOVA has a continuous outcome variable, and a categorical predictor, and (at least) one continuous covariate. Can this be run as a mediation model instead, and if so what are the ...
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16 views

Intepreting p values from R mediate() output

In the output below, the ACME p value shows that it is significant. But the p-value for Prop. Mediated Average is >10%. I thought Prop. Mediate is the proportion of the total effect mediated by the ...
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22 views

Why is path b mediation model insignificant? What does this mean?

Path b (mediator --> outcome variable) is not significant in my mediation model when I ran a regression even though the relationship between the mediator and outcome variable were significant in basic ...
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13 views

mediation or moderation

I've found the following: With increasing age, Variable X decreases. With increasing age, Variable Y increases. The X-Y correlation is negative. In my initial analysis, Y "explained" the negative ...
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14 views

mediation analysis in AMOS

my values in AMOS for mediation analysis are coming significant at .001 level (p value). can someone help me with the interpretation and is this level of significance acceptable in social sciences ...
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33 views

Mediation analysis with Likert scale mediator

For my master's thesis, I need to conduct a mediation analysis. My independent variable is the condition assigned, with three different conditions: high income, low income and neutral. I coded the IV ...
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1answer
39 views

Does an underpowered mediation/moderation SEM have an increased chance of Type I error?

A study I'm familiar with has been encouraged by its review board to take more participants. This seems a sensible request on general grounds, but the reviewers suggested that it was essential to ...
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68 views

Help needed interpreting medeff results in stata

I am new to using the medeff function. I am looking for basic help in how to read the results I got from my analysis. I got the following results: 1) Because the ACME mean is insignificant, does ...
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36 views

What's an intuitive way to remember the difference between mediation and moderation?

In my experience these two terms frequently confuse students. For teaching purposes I am looking for some way to help students distinguish between them. One way might be to show that the statistical ...
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28 views

Calculation of effect size for a mediation analysis with a dichotomous DV

I am using Haye's PROCESS macro to calculate the indirect effect (mediation) using a continuous IV, continuous mediator and a dichotomous DV. Haye's macro does not calculate an effect size for ...
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157 views

Multiple Hierarchical Regression - Procedure with mediation

I have a set of hypothesis that I am looking to test. The model is as follows: http://i.imgur.com/pdGRiyw.jpg (simplified to X -> M -> Y) ie. I am looking for direct effects from X -> Y, X -> M, M ...
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25 views

Mediation correlation

I have the following scenario in my research: In an open source software setting, we want to prove that when a project includes a lot of contributors who have collaborated before, then the project is ...
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13 views

Mediation using normalized variables

If I normalize (range 0-1) variables x, m, y prior to conduct a mediation (OLS), do I report them as "fully normalized coefficients". How do I interpret the results? I am used to report unstandardized ...
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29 views

Adjusting for mediating variables (everyone does it!)

I have always learned that when doing multivariable regression, one should not adjust for mediating variables between the independent and dependent variables of interest. I have seen in the academic ...
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52 views

summary measure of change over two timepoints to use as mediator in regression model

I am intending to analyze some pre- post- treatment data. My intention is to use ANCOVA to analyse treatment effects. However, in a separate analysis, I am going to test the hypothesis that the ...
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1answer
60 views

Mediation model: is it wrong?

From time to time it crosses my mind that the mediation model so widely used in psychology area of research is not a good model, because it 'works' when two variables are correlated. During my ...
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149 views

Is 'indirect effect' the same as 'mediation'?

Is it correct to use 'indirect effect' and 'mediation' interchangeably in all situations? I mean if we know that A influences B and B influences C. Can we conclude that the effect is mediated by B ...
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180 views

Is there evidence of mediation? Need help with interpretation of mediation analysis results

I have performed a mediation analysis. I have an independent variable T, a mediator M, and outcome Y. (All 3 variables are binary, and I use logit.) (While I used Stata ...
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1answer
99 views

Complete mediation (Preacher Hayes)

Below is the output of my bootstrap model (Preacher & Hayes, 2008). Path a, b and c are ...
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34 views

multilevel mediation with a proportion dependent variable sem

I am attempting to test an indirect path in a multilevel dataset with an outcome that is a proportion. The data are a collection of variables related to various qualities of potential support ...
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40 views

Is it Complete or Partial mediation? Or no mediation at all?

Kindly explain the given situation, is it partial, complete, or no mediation at all?
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24 views

Mean centering variables NOT in a moderation/interaction term [duplicate]

I am trying to assess the impact of multicollinearity in a regression because I have two separately measured variables which have the reversed signs problem (one predictor is +b regression weight, the ...
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59 views

What effect, if any, do outliers have on mediation analysis with bootstrapping?

I am running a mediation analysis spread over 6 models. Analysis is performed using the PROCESS macro. Each model includes 1 IV, 2 parallel mediators, and 1 DV. In a couple of the IVs, a number of ...
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35 views

Mediation analysis when IV and DV are dichotomous variables and a mediator is a continuous variable

I found a significant association between my dichotomous IV and my dichotomous DV using CrossTables and looking at Chi Square. Now I am interested in finding whether this association is mediated by a ...
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44 views

Mediation analysis using Bootstraps

I have used Hayes' plugins (PROCESS and INDIRECT) in SPSS. My result shows that all four paths (a,b,c,and c') are significant i.e. have a p-value of less than 0.05. In all the examples I have ...
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61 views

Multiple Mediation Analyses in Model

Hi everyone, I'm currently in the process of finalising my honours thesis in Psychology and have run some preliminary analyses testing for mediation. I was wondering if it is theoretically ...
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187 views

Need to transform data before running mediation/model with bootstrapping (PROCESS)?

I am reading through Hayes' book on mediation and moderation analysis (2013) which describes the PROCESS macro he created to use bootstrapping in order to arrive to confidence intervals to check the ...
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679 views

Is Baron and Kenny method for mediation now outdated?

Is Baron and Kenny method for mediation now outdated? This is because I got a comment from reviewer saying asking me to refer to Rucker, D.D., Preacher, K.J., Tormala, Z.L. & Petty, R.E. (2011). ...
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62 views

Is this mediation or a simple path?

This is my model adapted from a study. I want to know whether I can only study it as a path analysis without studying mediation effect (1 $\longrightarrow$ 5 direct effect, as well as indirect ...
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133 views

Generating non-normal correlated data for mediation analysis?

For a simulation study I have to generate data according to a trivariate mediation model (Baron & Kennys causal step approach). Assuming $X$, $M$, and $Y$ are continuous variables of sample size ...
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19 views

Mediation and moderation in labeling

So I'm looking at student stigma affecting self-esteem. The overall idea is that stigma affects student achievement through the mediator self-esteem, so I will do multiple regressions and test for ...
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2answers
419 views

mediator or moderator variable?

I have been given a set of data and I am confused as to whether one of the variables is a moderator or mediator variable. The hypothesis is that stress and well-being have an inverse relationship. ...
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1answer
70 views

How to determine whether an indirect effect is statistically significant using Bayesian statistics?

I've used bayesian estimation to test the indirect effects within a model and identified 95% credible intervals. I'm typically used to using the Sobel's z test to identify significant mediation, what ...
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78 views

testing for mediation of interactions

I am somewhat familiar with various ways of testing mediation for factors in different types of regression analysis. (I'm using R and currently working with a multilevel binary logistic regression.) ...
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31 views

SPSS mediational analysis help

I'm doing a psychology project and I'm struggling with statistics (SPSS) especially on meditational analysis. I have searched all over my notes from my bachelor degree but there is nothing on ...
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1answer
170 views

Variable A predicts B, variable B predicts C

I have pre - post data on quality of life, depression, and self-esteem. I hypothesize that changes in self-esteem from pre to post cause changes in depression, which in turn cause changes in quality ...
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1answer
917 views

Comprehending output from mediation analysis in R

I'm trying to get my head around the mediation package in R, using the vignette for the package. I'm struggling to understand the output of the mediate() ...
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2answers
1k views

mediation analysis when mediator is categorical (SPSS)

I want to do a mediation analysis, with the following variables: ...
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2answers
1k views

What test should I perform on a structural equation model?

This model is a replication of an earlier study. After factor analysis in SPSS, I need to test my hypothesis (as you can see there are 7) all should give significant positive relation with each ...
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80 views

Mediation on an interaction with dichotmous mediator

We are using Tingely et al's mediation R package for mediation analysis. Our study is a 2x2 design, say A (0 and 1) and B (0 and 1), with dichotomous mediator M and continuous dependent measure Y. Our ...