heldconstant

Held constant is a term used to describe the practice of keeping one or more variables fixed at specified values during analysis, experimentation, or modeling. The goal is to isolate the effect of a variable of interest and to mitigate the influence of other factors.

In experimental design and data collection, holding constants is central to control. By maintaining identical conditions across trials—such as temperature, duration, or equipment settings—researchers minimize variation that could obscure causal relationships. In factorial designs, some factors are held constant while others are varied to estimate main effects and interactions.

In statistics and mathematical modeling, constants may refer to parameters treated as fixed inputs. When a parameter is held constant, its value is not estimated from the current data, allowing equations or models to be solved or interpreted under that assumption. The concept is related to ceteris paribus, where all other relevant factors are kept unchanged.

In computing and simulation, a value may be designated as held constant to indicate that it should not change during a run. This can aid reproducibility and debugging, and is often conveyed through naming conventions or configuration settings.

See also: control variable, constant, ceteris paribus, experimental design, parameter.