  The rooting procedure commonly used with staggered fermions does not
correctly treat non-perturbative effects associated with gauge field topology.
In practice these effects are small for the physics of flavor non-singlet
particles. However large uncontrolled systematic errors are expected for flavor
singlet issues, such as the mass of the eta prime meson. While the relative
speed of the algorithm in large scale simulations may justify its use, the
method is an approximation and should not be promoted as a first principles
approach to the strong interactions.
