Friday, April 4, 2014

Mediation and moderation: Lecture related material

Key material

SPSS data set "gambling study v04.sav
Spreadsheet to create moderation figures
Table templates
Figure template for flow of participants for randomized control trials (RCT)
Figure template for reporting mediation results 
Word document with APA style

Lecture files (1 Feb 2017)

- PowerPoint file "Mediation-Moderation-2017.pptx"
- SPSS output file "gambling study output 2017.spv"
- SPSS syntax file for graph "gambling study syntax 2017.sps"
- SPSS data file "gambling study v04.sav"

Lecture slides (27 Jan 2016):
- PowerPoint file "Mediation-Moderation-2016-v08.pptx"
- PDF with six slides to each sheet file "Mediation-Moderation-2016-v08-6to1.pdf
- SPSS output file "gambling study output 2016.spv"
- SPSS syntax file for graph "gambling study syntax 2016.sps"

Lecture slides (6 Feb 2015): 
- PowerPoint file "2015-Mediation-Moderation-v07.pptx"
- PDF with six slides to each sheet "PSYC402H 2015 Mediation Moderation 6to1.pdf

Lecture video/audio (mp4) - Delivered April 2014

Power for mediation and moderation analyses

Please see


Video on Moderation and Mediation by Andy Field 


What about effect sizes for mediation?
Plenty of effect sizes reported in the output. When thinking about the effect size and which one to report/write about, think about the indirect (mediation) effect in relation to the total or direct effects (ratio). This type of discussion plus reporting the ratio might help you understand the 'size' of the effect size. Make sure you report at least one of the effect sizes in the output as per examples given in the lecture/output. 

Also, consider the suggestion that small, moderate, and large effect size criterion should be smaller for moderation type analysis, see: 

Aguinis, H., Beaty, J. C., Boik, R. J., & Pierce, C. A. (2005). Effect size and power in assessing moderating effects of categorical variables using multiple regression: A 30-year review. Journal of Applied Psychology, 90, 94-107. doi:10.1037/0021-9010.90.1.94

Difficulty downloading the above files
  • Try right-clicking the link and try any "save as" or "save link" options. 
  • If you are using Chrome and are logged in to Google you might like to click the file (Google will open the file as a preview) then you should have options at the top of the window to download the file.