How to calculate: - Average Effect Size (step 4) - Moderators (step 5)

Overview We will first go through “how” to do this. Then, we will repeat everything and explain “why” we do each step

At this point you have: (1) Effect sizes. (2) Sample sizes. (3) moderators

Step 1 - Transform “r” into Fisher’s z-to-r See formulas from my excel file

Step 2 - Weight by inverse variance See formulas from my excel file

Step 3 - Upload to SPSS in SPSS, file-open

Step 4 - Initiate “MeanES” macro Download from Lipsey/Wilson website Open YOUR DATASET Open a new syntax Put the following at the end of the syntax file  INCLUDE 'C:\Documents and Settings\Desktop\metaclub\MeanES.SPS'. Highlight the sentence Click run (blue triangle at top)

Step 5 - Calculate “MeanES” In syntax, type the following sentence:  MEANES ES = ES_zr /W = weight /PRINT IVZR. fyi – “ES_zr” is my name for the effect sizes “weight” is my name for the weight “/PRINT IVZR” converts output back to “r” Highlight and click run

Step 6 – Interpret output ES =.1225, p =.0000 Q = 1140, p =.0000

Now, let’s repeat and explain “why” Transform into Fisher’s z-to-r  Why? Weight by inverse variance  Why? Something about standard error? Mathew?

Now, let’s move to Moderators METAF – Categorical Moderators  INCLUDE 'C:\Documents and Settings\Desktop\metaclub\MetaF.SPS'.  METAF ES = ES_zr /W = weight /GROUP = ev1_subjecttype /PRINT IVZR. METAF – Continuous Moderators  INCLUDE 'C:\Documents and Settings\Desktop\metaclub\MetaREG.SPS'.  METAREG ES = ES_zr /W = weight /IVS = ev1_subjecttype /PRINT IVZR. fyi – can only run 2 macros in same session fyi – I run categorical moderators using both METAF and METAREG because answer different questions

Interpreting Categorical Macro Sig difference = 22.87, p =.0000

Interpreting Continuous Macro beta = , p =.0014

Now, to Multivariate METAREG can handle multiple variables  METAREG ES = ES_zr /W = weight /IVS = ev1_subjecttype ev2_stimulustype /PRINT IVZR. fyi – Can include as many variables as you wish. fyi - I believe you can include CATEGORICAL moderators IF: (1) they are dichotomous, (2) they are continuous and linear relationship

Interpreting Continuous Macro beta for each one, p value for each one overall r-squared

Finally, Interaction analysis Center each variable Create interaction term by multiplying together Enter all three into METAREG If interaction term is sig, then interaction exists How to graph the interaction? (next week)

FYI The club website has my excel file and the accompanying SPSS file. You also have my quals paper, so you can use the SPSS file to practice and see if your data match the quals paper. HOWEVER, the data will only match the CATEGORICAL moderator analysis (not the continuous moderator analysis) for reasons I don’t have time to go into.