The rise of the Nash-Sutcliffe efficiency in hydrology

The Nash-Sutcliffe efficiency (NSE) is commonly used as a model evaluation metric in hydrology, but its prominence is often taken for granted. This study explores the social factors behind its adoption. Introduced in 1970, the NSE gained traction as computational advancements spurred the growth of hydrological models and evaluation metrics. This, in turn, led to the need to converge on broadly accepted metrics. In 1990, a committee recommended the NSE alongside two other metrics. One of the main developers of SWAT, a widely used hydrological model, adopted only the NSE part of this recommendation, solidifying the NSE’s dominance. This storyline shows that the NSE’s primacy appears to be derived more from tradition than from any demonstration of technical superiority. To date, path dependence is visible in on-going research efforts resulting from the popularity of the NSE. This historical perspective highlights how social processes have shaped the way hydrological models are evaluated.