To summarize the study results, we accumulated data from 77 studies that
examined the relationship between the Tellegen Absorption Scale and
a measure of hypnotic susceptibility. We found no differences in effect
size among conference presentations, published or unpublished studies.
More recent studies had lower effect sizes than older ones. The type
of hypnotizability scale had a significant effect on the absorption
and hypnotizability relationship; with the CURSS and HGSA having the
lowest mean correlations followed by the SHSSC, HIP and Other Categories.
Depending on the hypnosis scale used, correlations between susceptibility
ranged from .25 to .41.
One criticism of meta-analysis is that the results of a meta-analytic
study are affected by publication bias. This refers to the hypothesized
tendency for studies with significant results to be published, or accepted
for conference presentations, while editors and reviewers generally
reject studies with statistically non-significant results. Accordingly
unpublished research would be expected to have lower mean effect sizes
than either those studies that have been published or were conference
presentations. We found no evidence of a publication bias in the present
literature sample. There were no statistically significant differences
in the mean effect sizes among published or unpublished studies, or
those studies presented at conferences or symposia.