responsiveness
n.the quality of reacting quickly and in a positive way to something. It shows how well a person or a machine answers a request or a change.
n.the quality of reacting quickly and appropriately to a stimulus, request, or change. Often used to describe the efficiency of customer service or the speed of a computer system.
“The company is famous for its responsiveness to customer complaints.”
“The new software update significantly improved the system's responsiveness when multiple applications are open.”
“Political analysts often measure the health of a democracy by the responsiveness of elected officials to the evolving needs and concerns of their constituents.”
Often paired with the preposition 'to' followed by the stimulus or group being addressed.
From responsive + -ness.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.