Hi listers;
I have a general statistical question. I wonder if it is correct to make comments on the mediation effect in a regression equation, without making Sobel z-test for its significance. I have recently seen in an article such a situation. Like that: A predicts B; when C is added to the equation, the effect of A on B weakens and somebody comments that C is partial mediatior. If the effect of A on B becomes insignificant, it is commented that C is full mediator without making significance test of Sobel Z. My second question is; I wonder if there is a way in SPSS to make Sobel Z test or an alternative method to test the significance of mediation effect. Becuse it is a bit time consuming to calculate Sobel Z in hand. Thanks in advance Mehmet Karakus ====================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 |
Mehmet -
I'm not sure about a way to make SPSS calculate Sobel's Z, but Kris Preacher has a website that will calculate Sobel's Z for you: http://people.ku.edu/~preacher/sobel/sobel.htm He also has some power analysis calculators and a few other goodies. It's a fun website to check out. Sara Sara M. House, M.A. Adjunct Faculty Loyola University Chicago, Psychology Department Email: [hidden email] Teaching: Research Methods, Psychology & Law ===================== 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 MKA-4
As Sara said Preacher's web site is a very good resource. He also
has macros (for SAS and SPSS) that will use bootstrapping to compute confidence intervals which seems to be a better test that just the pure sobel test. Preacher, K. J., & Hayes, A. F. (2008). Asymptotic and resampling strategies for assessing and comparing indirect effects in multiple mediator models. Behavior Research Methods, 40, 879-891. http://www.people.ku.edu/~preacher/ http://www.comm.ohio-state.edu/ahayes/SPSS%20programs/indirect.htm > -----Original Message----- > From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of MKA > Sent: Wednesday, October 01, 2008 7:47 AM > To: [hidden email] > Subject: significance of mediation effect - Sobel Z > > Hi listers; > I have a general statistical question. I wonder if it is correct to make > comments on the mediation effect in a regression equation, without making > Sobel z-test for its significance. I have recently seen in an article such a > situation. Like that: A predicts B; when C is added to the equation, the > effect of A on B weakens and somebody comments that C is partial mediatior. > If the effect of A on B becomes insignificant, it is commented that C is > full mediator without making significance test of Sobel Z. > My second question is; I wonder if there is a way in SPSS to make Sobel Z > test or an alternative method to test the significance of mediation effect. > Becuse it is a bit time consuming to calculate Sobel Z in hand. > > Thanks in advance > Mehmet Karakus > > ======= > 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 |
Absolutely. Sobel's test lacks power and depends on normality
assumptions. Bootstrapping has more power and is not dependent on normality assumptions. Paul R. Swank, Ph.D Professor and Director of Research Children's Learning Institute University of Texas Health Science Center Houston, TX 77038 -----Original Message----- From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Jeff Stuewig Sent: Wednesday, October 01, 2008 9:19 AM To: [hidden email] Subject: Re: significance of mediation effect - Sobel Z As Sara said Preacher's web site is a very good resource. He also has macros (for SAS and SPSS) that will use bootstrapping to compute confidence intervals which seems to be a better test that just the pure sobel test. Preacher, K. J., & Hayes, A. F. (2008). Asymptotic and resampling strategies for assessing and comparing indirect effects in multiple mediator models. Behavior Research Methods, 40, 879-891. http://www.people.ku.edu/~preacher/ http://www.comm.ohio-state.edu/ahayes/SPSS%20programs/indirect.htm > -----Original Message----- > From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of MKA > Sent: Wednesday, October 01, 2008 7:47 AM > To: [hidden email] > Subject: significance of mediation effect - Sobel Z > > Hi listers; > I have a general statistical question. I wonder if it is correct to make > comments on the mediation effect in a regression equation, without making > Sobel z-test for its significance. I have recently seen in an article such a > situation. Like that: A predicts B; when C is added to the equation, the > effect of A on B weakens and somebody comments that C is partial mediatior. > If the effect of A on B becomes insignificant, it is commented that C is > full mediator without making significance test of Sobel Z. > My second question is; I wonder if there is a way in SPSS to make Sobel Z > test or an alternative method to test the significance of mediation effect. > Becuse it is a bit time consuming to calculate Sobel Z in hand. > > Thanks in advance > Mehmet Karakus > > ======= > 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 ===================== 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 |
Free forum by Nabble | Edit this page |