upsilon() R function from [MBESS]

This function implements the upsilon effect size statistic as described in Lachowicz, Preacher, & Kelley (in press) for mediation.


upsilon(x, mediator, dv, conf.level = 0.95, bootstrap = TRUE, 
bootstrap.package = "lavaan", bootstrap.type="ordinary", B = 1000,
boot.data.out=FALSE, ...)

Arguments

x: x is the independent variable.
mediator: mediator is the mediator variable.
dv: dv is the outcome or dependent variable.
conf.level: conf.level is the desired confidence coefficient (i.e., the complement of the Type I error rate).
bootstrap: TRUE or FALSE regarding if a bootstrap confidence interval should be constructed
bootstrap.package: The package that will be used for bootstrapping, either lavaan or boot (default is lavaan).
bootstrap.type: The type of bootstrap confidence interval. If bootstrap.package = ``lavaan'', this can be either "ordinary" or"bollen.stine" (default is "ordinary"). If bootstrap.package = ``boot'', "normal", "basic", "student", "perc", or "bca" CIs (default is "perc".
B: The number of bootstrap replications (1000 is default)
boot.data.out: TRUE or FALSE regarding if bootstrap data is returned with function output (only available if bootstrap.boot = TRUE).
...: Allows specifictions for functions that are used within this function.

Returns

Returns the value of the effect size upsilon for a simple mediation model.

References

Lachowicz, M. J., Preacher, K. J., & Kelley, K. (in press). A novel measure of effect size for mediation analysis. Psychological Methods, X, X--X.

Preacher, K. J., & Kelley, K. (2011). Effect size measures for mediation models: quantitative strategies for communicating indirect effects. Psychological Methods, 16, 93--115.

Wen, Z., & Fan, X. (2015). Monotonicity of effect sizes: Questioning kappa-squared as mediation effect size measure. Psychological Methods, 20, 193--203.

Author(s)

Lachowicz Mark J. Lachowicz (Vanderbilt University; Mark.J.Lachowicz@Vanderbilt.edu )

Note

Note that this function overcomes some limitations of other effects for mediation models, such as those discussed in Preacher and Kelley (2012) and Wen and Fan (2015) and that was developed and delineated in Lachowicz, Preacher, and Kelley, K (in press). This function can only be used for simple mediation models at this time. Note that upsilon() was included in the mediation() function but it has become it's own function to provide more flexibility.

upsilon function