Quantifying phenotypic plasticity: A call for consistency

Abstract The interest of evolutionary, functional and applied ecologists in the study of phenotypic plasticity has grown considerably in recent decades. From being considered irrelevant in the mid‐20th century, phenotypic plasticity is now considered ubiquitous and essential for organisms to adapt to changing environments and to meet the challenges posed by anthropogenic global change. Consequently, an increasing number of studies are investigating phenotypic plasticity in many systems and ecological scenarios. This has led to the development of multiple and disparate methodological approaches. In this article, we propose a methodological framework that considers phenotypic plasticity as a trait property detected by constructing genotype‐based reaction norms that can be modelled using mixed‐effect models. We do not claim that this methodology is the only existing alternative for studying plasticity, but we believe it is a standard and consistent approach that allows for a rigorous assessment of the magnitude and between‐genotype variation in plasticity. Read the free Plain Language Summary for this article on the Journal blog.