Interpretation of VAF value

Spark

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Oct 22, 2015, 3:35:28 PM10/22/15

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Hi all,

While running mediation on SmartPLS the direct path coefficient was negative (as hypothesized) but the indirect path effect was positive. The VAF was calculated to be -0.06. Is this a suppressor effect? How do I interpret it? Please help.

Kind regards.

Ned Kock

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Oct 23, 2015, 9:03:27 AM10/23/15

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> [In a mediation test] the direct path coefficient was negative (as hypothesized) but the indirect path effect was positive. [...] Is this a suppressor effect?

I’ve seen this happening in WarpPLS analyses involving mediation in paths with 2 segments. If the two path coefficients for the links A > B and B > C are negative, the indirect effect coefficient for A > B > C will be positive, and thus of a sign that is different from those of the two component paths. This is not equivalent to Simpson’s paradox, or statistical suppression, which are different phenomena. For more details on these later phenomena, see the publications below.

Kock, N. (2015). WarpPLS 5.0 User Manual. Laredo, TX: ScriptWarp Systems.

http://www.scriptwarp.com/warppls/UserManual_v_5_0.pdf

Kock, N. (2015). How likely is Simpson’s paradox in path models? International Journal of e-Collaboration, 11(1), 1-7.

https://drive.google.com/file/d/0B76EXfrQqs3hc2dmM0xfMG0zZmM/view

Wasfeea

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Oct 24, 2015, 4:04:40 PM10/24/15

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Thank you Prof. Ned Kock

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