Degree of precision

The highest polynomial degree that a quadrature formula integrates exactly.

Definition

A formula has degree of precision mm if it integrates every polynomial of degree m\le m exactly and fails for some polynomial of degree m+1m+1. Simpson reaches degree 3 with only three nodes; Gauss-Legendre with nn nodes reaches 2n12n-1, the maximum possible.

How it is used

You check it by integrating the monomials 1,x,x2,1, x, x^2,\dots, and it is the quick way to compare formulas before looking at error constants.