sensivity

Sensivity is a term used in various fields to denote the degree to which a system responds to a given input or stimulus. In practice, the concept is close to sensitivity, and the spelling sensivity is often encountered as a variant. Across disciplines, the core idea is that a higher available response per unit input indicates greater sensivity, up to practical limits such as noise or saturation.

In measurement and sensors, sensitivity relates to the change in output produced by a unit change in input. It is typically expressed as a gain or transfer factor, such as volts per pascal for a pressure sensor or amperes per watt for a photodetector. Sensitivity is influenced by calibration, linearity, and noise, and is distinct from resolution or range.

In statistics and medicine, sensitivity is the true positive rate: the proportion of actual positives correctly identified by a test. High sensitivity reduces false negatives. It is paired with specificity, which measures true negatives. The two metrics underpin evaluation of diagnostic tools and screening programs and are central to ROC analysis.

In psychology and neurology, sensory sensitivity describes how readily an organism perceives stimuli, such as sound, light, or touch. Variations in sensitivity can reflect sensory processing differences, adaptation, or clinical conditions, and may influence behavior, comfort, and safety.

Ecology and engineering also use the term to describe how systems respond to perturbations, environmental changes, or inputs. In control systems, sensitivity functions quantify how outputs are affected by parameter variations, informing design and robustness.