Measurement practices in hallucinations research

David Smailes,Ben Alderson-Day,Cassie Hazell,Abigail Wright,Peter Moseley

doi:10.1080/13546805.2021.1999224

Abstract

ABSTRACT Introduction: In several sub-fields of psychology, there has been a renewed focus on measurement practices. As far as we are aware, this has been absent in hallucinations research. Thus, we investigated (a) cross-study variation in how hallucinatory experiences are measured and (b) the reliability of measurements obtained using two tasks that are widely employed in hallucinations research. Method: In Study 1, we investigated to what extent there was variation in how the Launay-Slade Hallucination Scale (LSHS) has been used across 100 studies. In Study 2, we investigated the reliability of the measurements obtained through source monitoring and signal detection tasks, using data from four recent publications. Materials/data are available at doi: 10.17605/osf.io/d3gnk/. Results: In Study 1, we found substantial variation in how hallucinatory experiences were assessed using the LSHS and that descriptions of the LSHS were often incomplete in important ways. In Study 2, we reported a range of reliability estimates for the measurements obtained using source monitoring and signal discrimination tasks. Some measurements obtained using source monitoring tasks had unacceptably low levels of reliability. Conclusions: Our findings suggest that suboptimal measurement practices are common in hallucinations research and we suggest steps researchers could take to improve measurement practices.

Highlights

In several sub-fields of psychology, there has been a renewed focus on measurement practices
It has been argued that the measurement practices psychology researchers engage in warrant increased attention, as accurately measuring our constructs-of-interest is a foundational part of psychological science
We excluded from this review studies that employed a translated version of the Launay-Slade Hallucination Scale (LSHS), as we did not have the expertise to verify how items have been translated studies that reported no other analysis than a factor analysis, and studies that reported no inferential tests

Summary

Introduction

In several sub-fields of psychology, there has been a renewed focus on measurement practices. This is a concern because, as shown by Parsons et al (2019), if the reliability of the measurements we obtain from the tasks we employ is low, the level of statistical power achieved in our studies is substantially reduced.

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Results

Conclusion