The Optimism\u2013Pessimism Short Scale\u20132 (SOP2): a comprehensive validation of the English-language adaptation

Désirée Nießen,Clemens M Lechner,Beatrice Rammstedt,Katharina Groskurth,Christoph J Kemper

doi:10.1186/s42409-021-00027-6

Abstract

The Optimism–Pessimism Short Scale–2 (SOP2) described in this article measures the psychological disposition of optimism with two items. SOP2 is the English-language adaptation of an originally for the German language developed scale. Because an empirical validation of this English-language SOP2 was hitherto lacking, the aim of the present study was to assess the psychometric properties (objectivity, reliability, validity) of the English-language adaptation and to investigate measurement invariance across both language versions using heterogeneous quota samples from the UK and Germany. Our results show that the English-language adaptation has satisfactory reliability coefficients and is correlated with 10 external variables in the study (e.g., self-esteem, Emotional Stability, life satisfaction). Moreover, scalar measurement invariance of the scale holds when comparing the UK and Germany, implying the comparability of latent (co)variances and latent means across the two nations. As an ultra-short scale with a completion time of < 20 s, SOP2 lends itself particularly to the assessment of dispositional optimism in survey contexts in which assessment time or questionnaire space are limited. It can be applied in a variety of research disciplines, such as psychology, sociology, or economics.

Highlights

Optimists and pessimists differ in their approach to the world (e.g., Carver et al, 2010)
Samples To investigate the psychometric properties of the English-language adaptation of Optimism–Pessimism Short Scale–2/Skala Optimismus–Pessimismus–2 (SOP2) and their comparability with those of the German-language source instrument, we assessed both versions in a Web-based survey that was conducted in the United Kingdom (UK) and Germany by the online access panel provider respondi AG
We investigated the factorial structure of SOP2 separately in the UK and Germany by means of confirmatory factor analyses (CFA) using the R package “lavaan” (Rosseel, 2012)

Summary

Introduction

Optimists and pessimists differ in their approach to the world (e.g., Carver et al, 2010). Whereas optimists look to the future with confidence and mostly expect good things to happen, pessimists are full of doubt when they look to the future and mostly expect bad things to happen. Studies investigating individual differences in optimism need a valid and efficient measure of this disposition, especially in research settings with severe time limitations. Motivated by this need, Kemper et al (2013) developed a two-item German-language measure of dispositional optimism, the Skala Optimismus–Pessimismus–2 (Optimism– Pessimism Short Scale–2; SOP2).

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