Transcript Slide 1

How to calculate:
- Average Effect Size (step 4)
- Moderators (step 5)
Overview
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We will first go through “how” to do this.
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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
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See formulas from my excel file
Step 2 - Weight by inverse variance
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See formulas from my excel file
Step 3 - Upload to SPSS
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in SPSS, file-open
Step 4 - Initiate “MeanES” macro
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Download from Lipsey/Wilson website
Open YOUR DATASET
Open a new syntax
Put the following at the end of the syntax file
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INCLUDE 'C:\Documents and Settings\Desktop\metaclub\MeanES.SPS' .
Highlight the sentence
Click run (blue triangle at top)
Step 5 - Calculate “MeanES”
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In syntax, type the following sentence:
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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”
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Highlight and click run
Step 6 – Interpret output
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ES = .1225, p = .0000
Q = 1140, p = .0000
Now, let’s repeat and explain “why”
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Transform into Fisher’s z-to-r
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Weight by inverse variance
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Why?
Why?
Something about standard error? Mathew?
Now, let’s move to Moderators
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METAF – Categorical Moderators
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INCLUDE 'C:\Documents and Settings\Desktop\metaclub\MetaF.SPS' .
METAF ES = ES_zr /W = weight /GROUP = ev1_subjecttype /PRINT IVZR.
METAF – Continuous Moderators
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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
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Sig difference = 22.87, p = .0000
Interpreting Continuous Macro
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beta = -.0201, p = .0014
Now, to Multivariate
METAREG can handle multiple variables
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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:
they are dichotomous,
(2) they are continuous and linear relationship
(1)
Interpreting Continuous Macro
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beta for each one, p value for each one
overall r-squared
Finally, Interaction analysis
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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
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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.