Hello,
I have a few questions regarding interpretation of my results for Mediation using Hayes' Process macro. The key point for finding significance is to see that the Class Interval does not include zero. However, in my mediation model, although the indirect effect CI doesn't include zero, the initial Models's CI (for bcope_ma, under Duration) includes zero. Should I still count my indirect effects as significant even though initial model for mediation is not significant? Results pasted below. Please Help! Thanks in advance! Model = 4 Y = qoltot X = duration M = bcope_ma Sample size 70 ************************************************************************** Outcome: bcope_ma Model Summary R R-sq F df1 df2 p .1830 .0335 2.3550 1.0000 68.0000 .1295 Model coeff se t p LLCI ULCI constant 22.5169 1.3151 17.1223 .0000 19.8927 25.1411 duration -.0388 .0253 -1.5346 .1295 -.0893 .0117 ************************************************************************** Outcome: qoltot Model Summary R R-sq F df1 df2 p .3234 .1046 3.9140 2.0000 67.0000 .0247 Model coeff se t p LLCI ULCI constant 91.2951 9.5536 9.5560 .0000 72.2258 110.3643 bcope_ma -1.0460 .3823 -2.7364 .0079 -1.8091 -.2830 duration .0059 .0811 .0725 .9425 -.1559 .1677 ************************** TOTAL EFFECT MODEL **************************** Outcome: qoltot Model Summary R R-sq F df1 df2 p .0674 .0045 .3102 1.0000 68.0000 .5794 Model coeff se t p LLCI ULCI constant 67.7413 4.3387 15.6134 .0000 59.0836 76.3990 duration .0465 .0834 .5570 .5794 -.1200 .2129 ***************** TOTAL, DIRECT, AND INDIRECT EFFECTS ******************** Total effect of X on Y Effect SE t p LLCI ULCI .0465 .0834 .5570 .5794 -.1200 .2129 Direct effect of X on Y Effect SE t p LLCI ULCI .0059 .0811 .0725 .9425 -.1559 .1677 Indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0406 .0311 .0009 .1240 Partially standardized indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0022 .0016 .0000 .0068 Completely standardized indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0589 .0411 .0017 .1650 Ratio of indirect to total effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .8736 149.0933 .1603 53.5001 Ratio of indirect to direct effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma 6.9093 17.9156 3.4423 275.8767 R-squared mediation effect size (R-sq_med) Effect Boot SE BootLLCI BootULCI bcope_ma .0045 .0173 -.0184 .0543 Preacher and Kelley (2011) Kappa-squared Effect Boot SE BootLLCI BootULCI bcope_ma .0601 .0401 .0066 .1692 Normal theory tests for indirect effect Effect se Z p .0406 .0318 1.2753 .2022 ******************** ANALYSIS NOTES AND WARNINGS ************************* Number of bootstrap samples for bias corrected bootstrap confidence intervals: 1000 Level of confidence for all confidence intervals in output: 95.00 NOTE: Some cases were deleted due to missing data. The number of such cases was: 33 |
The short answer is that if you are using a method such as bootstrapping to
test the Indirect Effect, then you need to only find a significant ab-path. If you are using a method like The Test of Joint Significance (TJS), then you would look to see if both a and b are different from 0. In your example - The test of the indirect effect is under "Total, Direct, and Indirect Effects". The CI for the Indirect Effect is [.0009,.1240] which doesn't include zero, so you would conclude that it is statistically significant (using bootstrapping criterion). So, you could have an "a" or "b" path that is non-significant, but the "ab" path is significant. However, the Total Effect is non-significant, indicating that there isn't an effect to mediate, to begin with. Do you expect a Total Effect (should X predict Y)? The Direct and Indirect Effects have the same sign, so you aren't dealing with "Inconsistent Mediation" (a suppression effect). So, you could talk about having an Indirect Effect but not Mediation. Also, you should look at the size of the Indirect Effect. It seems small - is this an important effect or is it trivial? pl -----Original Message----- From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of psy_vm Sent: Thursday, July 24, 2014 12:17 AM To: [hidden email] Subject: [SPSSX-L] Interpreting Mediation results Hello, I have a few questions regarding interpretation of my results for Mediation using Hayes' Process macro. The key point for finding significance is to see that the Class Interval does not include zero. However, in my mediation model, although the indirect effect CI doesn't include zero, the initial Models's CI (for bcope_ma, under Duration) includes zero. Should I still count my indirect effects as significant even though initial model for mediation is not significant? Results pasted below. Please Help! Thanks in advance! Model = 4 Y = qoltot X = duration M = bcope_ma Sample size 70 ************************************************************************** Outcome: bcope_ma Model Summary R R-sq F df1 df2 p .1830 .0335 2.3550 1.0000 68.0000 .1295 Model coeff se t p LLCI ULCI constant 22.5169 1.3151 17.1223 .0000 19.8927 25.1411 duration -.0388 .0253 -1.5346 .1295 -.0893 .0117 ************************************************************************** Outcome: qoltot Model Summary R R-sq F df1 df2 p .3234 .1046 3.9140 2.0000 67.0000 .0247 Model coeff se t p LLCI ULCI constant 91.2951 9.5536 9.5560 .0000 72.2258 110.3643 bcope_ma -1.0460 .3823 -2.7364 .0079 -1.8091 -.2830 duration .0059 .0811 .0725 .9425 -.1559 .1677 ************************** TOTAL EFFECT MODEL **************************** Outcome: qoltot Model Summary R R-sq F df1 df2 p .0674 .0045 .3102 1.0000 68.0000 .5794 Model coeff se t p LLCI ULCI constant 67.7413 4.3387 15.6134 .0000 59.0836 76.3990 duration .0465 .0834 .5570 .5794 -.1200 .2129 ***************** TOTAL, DIRECT, AND INDIRECT EFFECTS ******************** Total effect of X on Y Effect SE t p LLCI ULCI .0465 .0834 .5570 .5794 -.1200 .2129 Direct effect of X on Y Effect SE t p LLCI ULCI .0059 .0811 .0725 .9425 -.1559 .1677 Indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0406 .0311 .0009 .1240 Partially standardized indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0022 .0016 .0000 .0068 Completely standardized indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0589 .0411 .0017 .1650 Ratio of indirect to total effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .8736 149.0933 .1603 53.5001 Ratio of indirect to direct effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma 6.9093 17.9156 3.4423 275.8767 R-squared mediation effect size (R-sq_med) Effect Boot SE BootLLCI BootULCI bcope_ma .0045 .0173 -.0184 .0543 Preacher and Kelley (2011) Kappa-squared Effect Boot SE BootLLCI BootULCI bcope_ma .0601 .0401 .0066 .1692 Normal theory tests for indirect effect Effect se Z p .0406 .0318 1.2753 .2022 ******************** ANALYSIS NOTES AND WARNINGS ************************* Number of bootstrap samples for bias corrected bootstrap confidence intervals: 1000 Level of confidence for all confidence intervals in output: 95.00 NOTE: Some cases were deleted due to missing data. The number of such cases was: 33 -- View this message in context: http://spssx-discussion.1045642.n5.nabble.com/Interpreting-Mediation-results -tp5726809.html Sent from the SPSSX Discussion mailing list archive at Nabble.com. ===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD ===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD |
In reply to this post by psy_vm
Have you checked out Hayes website?
http://www.afhayes.com/spss-sas-and-mplus-macros-and-code.html and also perhaps http://www.afhayes.com/macrofaq.html Muir Houston, HNC, BA (Hons), M.Phil., PhD, FHEA College of Social Sciences Ethics Officer Social Justice, Place and Lifelong Education Research School of Education University of Glasgow 0044+141-330-4699 Silver bullet or red herring? New evidence on the place of aspirations in education R3L+ Project - Adult education in the light of the European Quality Strategy http://www.learning-regions.net/ GINCO Project - Grundtvig International Network of Course Organisers http://www.ginconet.eu/ THEMP - Tertiary Higher Education for People in Mid Life http://themp.eu/ -----Original Message----- From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of psy_vm Sent: 24 July 2014 08:17 To: [hidden email] Subject: Interpreting Mediation results Hello, I have a few questions regarding interpretation of my results for Mediation using Hayes' Process macro. The key point for finding significance is to see that the Class Interval does not include zero. However, in my mediation model, although the indirect effect CI doesn't include zero, the initial Models's CI (for bcope_ma, under Duration) includes zero. Should I still count my indirect effects as significant even though initial model for mediation is not significant? Results pasted below. Please Help! Thanks in advance! Model = 4 Y = qoltot X = duration M = bcope_ma Sample size 70 ************************************************************************** Outcome: bcope_ma Model Summary R R-sq F df1 df2 p .1830 .0335 2.3550 1.0000 68.0000 .1295 Model coeff se t p LLCI ULCI constant 22.5169 1.3151 17.1223 .0000 19.8927 25.1411 duration -.0388 .0253 -1.5346 .1295 -.0893 .0117 ************************************************************************** Outcome: qoltot Model Summary R R-sq F df1 df2 p .3234 .1046 3.9140 2.0000 67.0000 .0247 Model coeff se t p LLCI ULCI constant 91.2951 9.5536 9.5560 .0000 72.2258 110.3643 bcope_ma -1.0460 .3823 -2.7364 .0079 -1.8091 -.2830 duration .0059 .0811 .0725 .9425 -.1559 .1677 ************************** TOTAL EFFECT MODEL **************************** Outcome: qoltot Model Summary R R-sq F df1 df2 p .0674 .0045 .3102 1.0000 68.0000 .5794 Model coeff se t p LLCI ULCI constant 67.7413 4.3387 15.6134 .0000 59.0836 76.3990 duration .0465 .0834 .5570 .5794 -.1200 .2129 ***************** TOTAL, DIRECT, AND INDIRECT EFFECTS ******************** Total effect of X on Y Effect SE t p LLCI ULCI .0465 .0834 .5570 .5794 -.1200 .2129 Direct effect of X on Y Effect SE t p LLCI ULCI .0059 .0811 .0725 .9425 -.1559 .1677 Indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0406 .0311 .0009 .1240 Partially standardized indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0022 .0016 .0000 .0068 Completely standardized indirect effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .0589 .0411 .0017 .1650 Ratio of indirect to total effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma .8736 149.0933 .1603 53.5001 Ratio of indirect to direct effect of X on Y Effect Boot SE BootLLCI BootULCI bcope_ma 6.9093 17.9156 3.4423 275.8767 R-squared mediation effect size (R-sq_med) Effect Boot SE BootLLCI BootULCI bcope_ma .0045 .0173 -.0184 .0543 Preacher and Kelley (2011) Kappa-squared Effect Boot SE BootLLCI BootULCI bcope_ma .0601 .0401 .0066 .1692 Normal theory tests for indirect effect Effect se Z p .0406 .0318 1.2753 .2022 ******************** ANALYSIS NOTES AND WARNINGS ************************* Number of bootstrap samples for bias corrected bootstrap confidence intervals: 1000 Level of confidence for all confidence intervals in output: 95.00 NOTE: Some cases were deleted due to missing data. The number of such cases was: 33 -- View this message in context: http://spssx-discussion.1045642.n5.nabble.com/Interpreting-Mediation-results-tp5726809.html Sent from the SPSSX Discussion mailing list archive at Nabble.com. ===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD ===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD |
In reply to this post by peter link
From: peter link [via SPSSX Discussion] <[hidden email]>; To: psy_vm <[hidden email]>; Subject: Re: Interpreting Mediation results Sent: Thu, Jul 24, 2014 5:12:02 PM
|
In reply to this post by peter link
From: peter link [via SPSSX Discussion] <[hidden email]>; To: psy_vm <[hidden email]>; Subject: Re: Interpreting Mediation results Sent: Thu, Jul 24, 2014 5:12:02 PM
|
I’m not familiar with PROCESS but from the output it looks
like an R-sq and Kappa-sq is provided. This is towards the bottom of the
output. Is this different than what you are asking about? By the way, Andrew Hayes has an email address listed on his
website. Perhaps, go to his website and contact him directly. Peter From: SPSSX(r) Discussion
[mailto:[hidden email]] On Behalf Of psy_vm
From:
peter
link [via SPSSX Discussion] <[hidden
email]>;
View
this message in context: Re:
Interpreting Mediation results |
From: peter link [via SPSSX Discussion] <[hidden email]>; To: psy_vm <[hidden email]>; Subject: Re: Interpreting Mediation results Sent: Fri, Aug 15, 2014 11:26:51 PM
|
Hi - Those are regression/path coefficients or products thereof
and not effect sizes. The Total Effect: The effect of X on Y. Often this is labeled as
the c path. The Direct Effect: The effect of X on Y adjusting for M. Often
this is labeled as the c’ path. The Indirect Effect: The product of the effects of X on M (a
path) and M on Y (b path). Often this product is labeled as the ab path. Hope this helps. peter From: SPSSX(r) Discussion
[mailto:[hidden email]] On Behalf Of psy_vm
From:
peter
link [via SPSSX Discussion] <[hidden
email]>;
View
this message in context: Re:
Interpreting Mediation results |
From: peter link [via SPSSX Discussion] <[hidden email]>; To: psy_vm <[hidden email]>; Subject: Re: Interpreting Mediation results Sent: Mon, Aug 18, 2014 3:09:31 PM
|
Free forum by Nabble | Edit this page |