Constraint

A constraint is a limitation of possibilities, in particular a restriction of the feasible solutions in an optimization problem.

In the theory of constraints it is any factor that limits the performance of a system with respect to its goal.

Eliyahu M. Goldratt maintains that any business system has

• at least one constraint, otherwise it's performance would be infinite
• very few constraints, otherwise it would be unstable and cease to exist.

The concept of constraint is the basis for Goldratt's process of focused improvement.

See also restraint, Donella Meadows' twelve leverage points to intervene in a system

For constraints in literature, see constrained writing.