[R-meta] Egger Sandwich Test & Correlated Hierarchical Effects (Plus) Model

[Sicong Liu]

Dear All,

I would like to ask two questions, one about the correlated hierarchical effects (CHE) model and the other about Egger Sandwich test used in CHE.

  *   I am meta-analyzing a dataset consisting of ~400 effect sizes (converted from logOR to d) from 98 independent group comparisons, which is from 88 clinical trials. I have more independent group comparisons than trials because a few trials have separate reports for subgroups of their samples. For example, a trial may separately report outcomes from adolescents and adults in the sample. I am planning to use the correlated hierarchical effect (CHE) approach and wonder whether I should use the CHE (i.e., two levels such as �independent sample / ES�) or the CHE+ (three levels such as �trial / independent sample / ES�). Based on some preliminary results, it seems that the 2nd level variance component would turn 0 in CHE+ models. In such a case, I wonder if I should use CHE instead of CHE+? If I can use CHE, a related questions is, is it better to use �independent sample / ES� or �trial / ES?�
  *   I am also planning to run Egger Sandwich test with the above meta-regression models. Based on the example from Rodgers & Pustejovsky (2021), see reference below, is it better to use the standard error version or the variance version of the precision (i.e., the modified variance term named W in below Pustejovsky & Rodgers, 2019). In addition, Rodgers & Pustejovsky (2021) seems to recommend use one-sided t test for detecting selective reporting in Egger Sandwich test. Does it make it wrong to use two-sided t test associated with the precision term in Egger Sandwich test?
     *   Rodgers, M. A., & Pustejovsky, J. E. (2021). Evaluating meta-analytic methods to detect selective reporting in the presence of dependent effect sizes. Psychological methods, 26(2), 141.
     *   Pustejovsky, J. E., & Rodgers, M. A. (2019). Testing for funnel plot asymmetry of standardized mean differences. Research Synthesis Methods, 10(1), 57-71.

Thank you very much!

Best regards,
Sicong (Zone)

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Sicong (Zone) Liu, Ph.D.
Research Associate
University of Pennsylvania

3620 Walnut Street,
Philadelphia, PA 19104-6220
Email: zone using upenn.edu<mailto:zone using upenn.edu>
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