Tighter lending standards are a necessary correction after the late-cycle excesses on the part of underwriters, but also mean that many sub-prime borrowers will have difficulty refinancing.

Once the terrain related parameters are calculated, the necessary correction factors can be added or subtracted as required.

This information was sent to an analog computer which calculated the trajectory and any necessary correction to hit the target.

Opticians determine the specifications of various ophthalmic appliances that will give the necessary correction to a person's eyesight.

The necessary corrections could not be clearer.