Publication bias, the fact that studies identified for inclusion in a meta analysis do not represent all studies on the topic of interest, is commonly recognized as a threat to the validity of the results of a meta analysis. One way to explicitly model publication bias is via selection models or weighted probability distributions. In this package we provide implementations of several parametric and nonparametric weight functions. The novelty in Rufibach (2011) is the proposal of a non-increasing variant of the nonparametric weight function of Dear & Begg (1992). The new approach potentially offers more insight in the selection process than other methods, but is more flexible than parametric approaches. To maximize the log-likelihood function proposed by Dear & Begg (1992) under a monotonicity constraint we use a differential evolution algorithm proposed by Ardia et al (2010a, b) and implemented in Mullen et al (2009). In addition, we offer a method to compute a confidence interval for the overall effect size theta, adjusted for selection bias as well as a function that computes the simulation-based p-value to assess the null hypothesis of no selection as described in Rufibach (2011, Section 6).
|Author||Kaspar Rufibach <firstname.lastname@example.org>|
|Date of publication||2015-07-03 12:51:10|
|Maintainer||Kaspar Rufibach <email@example.com>|
|License||GPL (>= 2)|
DearBegg: Compute the nonparametric weight function from Dear and Begg...
DearBeggMonotoneCItheta: Compute an approximate profile likelihood ratio confidence...
DearBeggMonotonePvalSelection: Compute simulation-based p-value to assess null hypothesis of...
education: Dataset open vs. traditional education on creativity
effectBias: Compute bias for each effect size based on estimated weight...
IyenGreen: Compute MLE and weight functions of Iyengar and Greenhouse...
passive_smoking: Dataset on the effect of environmental tobacco smoke
pPool: Pool p-values in pairs
Pval: Functions for the distribution of p-values
selectMeta-package: Estimation of Weight Functions in Meta Analysis
weightLine: Function to plot estimated weight functions