Does it matter if there are errors in GHQ-12 response items?
Authors: Bethany Croak, Neil Greenberg, Danielle Lamb, Sharon A M Stevelink, Simon Wessely
Journal: The Lancet Psychiatry (2024)

The General Health Questionnaire (GHQ), particularly the GHQ-12, is widely used in epidemiological research to detect symptoms of probable psychiatric disorders.1Goldberg DP The detection of psychiatric illness by questionnaire. Oxford University Press, London1972Google Scholar Questionnaire transcription errors can occur in multiple ways, including when converting a printed version to an online version. In March, 2023, we discovered we had made a transcription error in several waves of data we collected as part of a longitudinal study among health-care workers. The GHQ-12 has twelve items, each answered on a four-point Likert scale, with answers indicating better wellbeing on the left and worse wellbeing on the right. In creating response options for item eight of the GHQ-12 in our survey, the first response option was mistakenly labelled "not at all" when it should have been labelled "more so than usual", resulting in responses at both ends of the scale potentially indicating worse wellbeing. Several of our publications included results derived from the GHQ-12,2Lamb D Gnanapragasam S Greenberg N et al.Psychosocial impact of the COVID-19 pandemic on 4378 UK healthcare workers and ancillary staff: initial baseline data from a cohort study collected during the first wave of the pandemic.Occup Environ Med. 2021; 78: 801-808Crossref PubMed Scopus (70) Google Scholar, 3Williamson V Lamb D Hotopf M et al.Moral injury and psychological wellbeing in UK healthcare staff.J Ment Health. 2023; 32: 890-898Crossref PubMed Scopus (8) Google Scholar including an Article in The Lancet Psychiatry.4Scott HR Stevelink SAM Gafoor R et al.Prevalence of post-traumatic stress disorder and common mental disorders in health-care workers in England during the COVID-19 pandemic: a two-phase cross-sectional study.Lancet Psychiatry. 2023; 10: 40-49Summary Full Text Full Text PDF PubMed Google Scholar Following this realisation, we conducted analyses to ascertain whether our results might have been affected across various data waves. We examined the data with and without the erroneous item, comparing prevalence rates with mean and median substitution for the flawed item. Neither substitution method affected the results. Removing borderline cases (ie, cases with scores of three or four following the 0–0-1–1 scoring method, with a score of four indicating caseness) also did not alter prevalence. We hypothesised that as the error featured towards the end of the questionnaire, individuals had learnt responses on the left meant better wellbeing and continued to tick responses on the basis of this logic, negating the wrong wording in item eight. To test this hypothesis definitively, we used a market research panel to establish whether item errors would make a difference in a new population. Participants (N=1504) were randomly allocated to one of three groups and provided with one of the following GHQ-12 versions: a correct version (n=500); a version with an error in item eight (n=502); or a version with a purposeful error in item one (n=502). We included an error in item one to test whether the position of the error had any effect. The results, reported in a preprint,5Croak B Bhundia R Lamb D et al.Do errors in the GHQ-12 response options matter?.OSF Preprints. 2024; (published online Feb 27.) (preprint).https://doi.org/10.31219/osf.io/34a6pGoogle Scholar were clear that there was no difference in mean GHQ-12 scores or the proportion of cases for any of the three groups. These results confirm that our transcription error made no difference to the conclusions of our Article in The Lancet Psychiatry or any others. These findings can also reassure other researchers who might have made similar mistakes. We declare no competing interests. Prevalence of post-traumatic stress disorder and common mental disorders in health-care workers in England during the COVID-19 pandemic: a two-phase cross-sectional studyThe prevalence estimates of common mental disorders and PTSD in health-care workers were considerably lower when assessed using diagnostic interviews compared with screening tools. 21·5% of health-care workers met the threshold for diagnosable mental disorders, and thus might benefit from clinical intervention. Full-Text PDF Open Access