Changein

Changein is a term used to describe the amount by which a quantity changes between two states or moments. In everyday usage the phrase change in is more common, while changein may appear as a variable name or identifier in programming, data schemas, or documentation. The concept is fundamental to measuring differences over time, conditions, or scenarios, and is widely used across disciplines such as mathematics, statistics, economics, and science.

Definitions and variants: Absolute change equals the final value minus the initial value. Percent change equals the absolute change divided by the initial value, multiplied by 100 percent. When the initial value is zero, percent change is undefined or handled with special conventions. Change can be computed for single values or across arrays, time series, or experimental groups. Sometimes the change is described as a rate of change when divided by the time interval.

Applications include data analysis, finance, and science. In finance, change in prices or returns is used to assess performance. In statistics and economics, change in a variable helps study treatment effects or trend directions. In environmental and health sciences, changes in temperature, emissions, or biometrics are used to monitor progress and outcomes.

Example: A stock price moves from 150 to 165. The absolute change is +15, and the percent change is +10%. If the initial value is 0, such as certain measurements, the percent change is not defined, and analysts often use alternative metrics such as relative change with a different baseline or normalized values.