Luppo Kuillman

Chapter 4 92 samples. For correlation analysis, we used the parametric version of Pearson’s r, as all of the continuous variables had been transformed towards normality (Templeton & Burney, 2016). Multivariate analysis A regression-based moderation analysis was applied. We computed the a priori minimum sample size (given an alpha value of 0.05, a power of 0.80, and an effect size of f2=0.15) to determine the appropriateness of conducting a moderation analysis. Based on the outcome (minimum=68) and the sample size of the current study (n=155), moderation analysis was deemed permissible. The moderation analysis was performed based on a built-in bootstrap procedure of 5000 replications. All analyses, both bivariate and multivariate, were performed using IBM SPSS v. 25, and the regression-based moderation analysis was conducted by using the PROCESS SPSS macro, version 3.4. The computation of the minimum required sample-size for moderation analysis was performed using G*Power (Faul, Erdfelder, Buchner, & Lang, 2009). To plot the cross-over interaction effects of the unstandardized variables, we used an Excel spreadsheet made available by Professor James Gaskin (Gaskin, 2016). Ethical considerations According to the statement by the Dutch Central Committee on Research Involving Human Subjects (www.ccmo.nl ), no institutional review board approval was warranted for this type of survey with voluntary participation of professionals. An information letter sent to all respondents notified them of a) the purpose of the study, b) the voluntary nature of participation, and their right to stop participating in the study at any time. The respondents were also informed that their answers would be completely anonymous and that they would not be used for any purpose other than the study. Furthermore, the letter clearly addressed the expected average time needed to complete the questionnaires (45 minutes). This study was performed in accordance with the tenets of the Declaration of Helsinki (General Assembly of the World Medical Association, 2014). Only the first author (LK) had access to the encrypted data. The “Strengthening the Reporting of Observational Studies in Epidemiology” (STROBE) checklist was followed as a guideline for reporting on observational research.