Factor structure, measurement equivalence, and reliability of the Nature Relatedness Scale Short Form (NR-6) across males and females

Abstract

Nature relatedness is an important construct in environmental psychology and has frequently been measured using the NR-6, a six-item unidimensional short form scale. The NR-6 was developed using exploratory factor analysis on a sample of undergraduates and community members, but subsequent validity evidence is limited. This is concerning because the NR-6 comprises items from two nature relatedness dimensions, making it unclear whether researchers should use the NR-6 as a unidimensional or multidimensional scale. Poor validity evidence also threatens the interpretability of observed NR-6 scores across groups (e.g., results from t-tests). The purpose of the study was to evaluate the factor structure, measurement equivalence, and reliability of the NR-6 across males and females using an independent sample from the Open-Source Psychometrics Project (n = 1,522). Results revealed challenges when comparing observed NR-6 scores across males and females. Both unidimensional and multidimensional factor structures were plausible specifications for the NR-6, but the multidimensional model demonstrated superior fit. However, regardless of whether the NR-6 was treated as a unidimensional or multidimensional scale, observed mean differences between males and females were inflated. Additionally, the multidimensional NR-6 demonstrated reliability that was unacceptable for research purposes for both males and females. To appropriately use the NR-6 on a case-by-case basis, I recommend that researchers 1) always report structural validity and reliability evidence and 2) adjust analyses accordingly, when necessary, using structural equation modeling techniques.