MASON PSYC 612 - Introduction to Mediation

Unformatted text preview:

PSYC 612, SPRING 2012Introduction to MediationLecture Week: 2/14/2012Contents1 Preliminary Questions 12 Part I: Preview of Mediation and Moderation (30 minutes; 2 minute break) 22.1 Purpose: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.2 Objectives: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.3 Mediation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22.4 Moderation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Part II: Demonstrate a Mediational Analysis (50 minutes) 33.1 Purpose: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.2 Objectives: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.3 The Data and Mediation Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.4 Mediation Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.4.1 The Baron and Kenny method . . . . . . . . . . . . . . . . . . . . . . . . . . 43.4.2 The Sobel Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53.5 Mediational Model Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Part III: Practice Mediational Analysis (30 minutes) 54.1 Purpose: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.2 Objectives: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Part IV: Beyond the readings (15 minutes; 2 minute break) 65.1 Purpose: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.2 Objectives: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.3 Temporal contiguity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.4 Standard Errors, Errors of Inference and the Bootstrap . . . . . . . . . . . . . . . . 71 Preliminary Questions• How are the modules going?• Did you read the Iacobucci text?12 Part I: Preview of Mediation and Moderation (30 min-utes; 2 minute break)2.1 Purpose:Provide you with the necessary background information about the topics mediation and moderation2.2 Objectives:1. Introduce mediation2. Introduce moderation and contrast it with mediation2.3 MediationMediation is best explained graphically. We begin with a simple path diagram - note the similarityto my advance organizer?A CcThat path model depicts a single manifest variable A predicting a single manifest variable C - abivariate relationship often expressed as a correlation or a bivariate regression c. Causal inferencegets a bit more complicated when we introduce another variable into the fold. Typically, we justinclude that additional variable as another predictor of our oucome c as depicted here:ABCcbWhat happens when we expect a temporal relationship between our antecedent A and ourconsequence C to be causally related to our second predictor B? A relationship like that is depictedas:ABCc0a b2The model above shows a mediation model whereby B mediates (i.e., sits between) the an-tecedent A and the consequence C. Unfortunately, we learned that the GLM restricts us to a singledependent variable; thus, we cannot simultaneously analyze prediction of C by A and B along withthe prediction of B by A. The solution to this problem is the basis for today’s discussion - mediationanalysis.2.4 ModerationBefore we get to mediation, I want to contrast mediation with moderation. Many of you alreadyknow about moderation because moderation is nothing more than an interaction. This figure showsa moderated relationship for our three aforementioned variables:ABCcab3 Part II: Demonstrate a Mediational Analysis (40 min-utes)3.1 Purpose:Solidify conceptual knowledge with an example3.2 Objectives:1. Describe data and model2. Run mediational analysis3. Discuss results in detail3.3 The Data and Mediation ModelA recent Department of Education report on the “Equity in Athletics” provided us with a conve-nient dataset to demonstrate mediational models. I am only using a small portion of the data forillustrative purposes only. There are probably better datasets than this one but it is current andreasonably interesting so that we can all have some fun. You may find the data on the MRESwebsite; please download it if you care to run the same models I run below.The data need litle explanation other than to say that these variables relate to athletic de-partment revenue and expenditures. I am interested in relating student body size (Nstudents) to3Ns FinAid Recruiting HeadCoaches Revenue ExpensesNsFinAid 0.16Recruiting 0.37 0.61HeadCoaches 0.36 0.72 0.47Revenue 0.55 0.63 0.82 0.59Expenses 0.54 0.66 0.82 0.61 0.98Profit 0.38 0.27 0.51 0.28 0.68 0.55Table 1: Correlation of relevant variablesrecruiting expenses and profit. My model would look like the basic mediational model we discussedpreviously:Number of StudentsRecruiting ExpensesProfitNumber of Students Profitc0a bc3.4 Mediation AnalysisThere are many ways to analyze this simple mediational model. Perhaps the easiest is to usethe (now) classic Baron and Kenny method. Other methods exist and most are superior to theirapproach. …


View Full Document

MASON PSYC 612 - Introduction to Mediation

Download Introduction to Mediation
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Introduction to Mediation and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Introduction to Mediation 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?