New Paper: Reproducibility of Individual Effect Sizes in Psychological Meta-Analyses

I am happy to announce that our paper “Reproducibility of individual effect sizes in meta-analyses in psychology” was published in PLoS One (first-authored by Esther Maassen). In this study, we assessed 500 primary effect sizes from 33 psychology meta-analyses. Reproducibility was problematic in 45% of the cases (see Figure below for different causes). We strongly recommend meta-analysts to share their data and code.

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Top Downloaded Paper

I am very happy to announced that my paper “Practical tools and strategies for researchers to increase replicability” was listed as a Top Download for the journal Developmental Medicine & Child Neurology.

The paper lists an overview of concrete actions researchers can undertake to improve the openness, replicability, and overall robustness of their work.

I hope that the high number of downloads indicate that many researchers were able to cherry-pick open practices that worked for their situation.

Read the full paper (open access) here.

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In Press: Practical Tools and Strategies for Researchers to Increase Replicability

I wrote an invited review for Developmental Medicine & Child Neurology about “Practical tools and strategies for researchers to increase replicability”.

Problems with replicability have been widely discussed over the last years, especially in psychology. By now, a lot of promising solutions have been proposed, but my sense is that researchers are sometimes a bit overwhelmed by all the possibilities.

My goal in this review was to make a list of some of the current recommendations that can be easily implemented. Not every solutions is always feasible for every project, so my advice is: copy best practices from other fields, see what works on a case-by-case basis, and improve your research step by step.

The preprint can be found here: https://psyarxiv.com/emyux.

New Preprint: Effect Sizes, Power, and Biases in Intelligence Research

Our new meta-meta-analysis on intelligence research is now online as a preprint at https://psyarxiv.com/ytsvw.

We analyzed 131 meta-analyses in intelligence research to investigate effect sizes, power, and patterns of bias. We find a typical effect of r = .26 and a median sample size of 60.

The median power seems low (see figure below), and we find evidence for small study effects, possibly indicating overestimated effects. We don’t find evidence for a US effect, decline or early-extremes effect, or citation bias.

MedianPowerPerTypeAndOverallRandomEffects

Comments are very welcome and can be posted on the PubPeer page https://pubpeer.com/publications/9F209A983618EFF9EBED07FDC7A7AC.

 

New Preprint: statcheck’s Validity is High

In our new preprint we investigated the validity of statcheck. Our main conclusions were:

  • statcheck’s sensitivity, specificity, and overall accuracy are very high. The specific numbers depended on several choices & assumptions, but ranged from:
    • sensitivity: 85.3% – 100%
    • specificity: 96.0% – 100%
    • accuracy: 96.2% – 99.9%
  • The prevalence of statistical corrections (e.g., Bonferroni, or Greenhouse-Geisser) seems to be higher than we initially estimated
  • But: the presence of these corrections doesn’t explain the high prevalence of reporting inconsistencies in psychology

We conclude that statcheck’s validity is high enough to recommend it as a tool in peer review, self-checks, or meta-research.

statcheck-01

New Preprint: Data Sharing & Statistical Inconsistencies

We just published the preprint of our new study “Journal Data Sharing Policies and Statistical Reporting Inconsistencies in Psychology” at https://osf.io/preprints/psyarxiv/sgbta.

In this paper, we ran three independent studies to investigate if data sharing is related to fewer statistical inconsistencies in a paper. Overall, we found no relationship between data sharing and reporting inconsistencies. However, we did find that journal policies on data sharing are extremely effective in promoting data sharing (see the Figure below).

EffectivenessOpenDataPolicy

We argue that open data is essential in improving the quality of psychological science, and we discuss ways to detect and reduce reporting inconsistencies in the literature.