After the search has been completed, action is taken in the light of the references found. Where the assistant examiner has been in the Office but a short time, it is the duty of the primary examiner to review the application thoroughly. The usual procedure is for the assistant examiner to explain the invention and discuss the references which he or she regards as most pertinent. The primary examiner may indicate the action to be taken, whether restriction or election of species is to be required, or whether the claims are to be considered on their merits. If action on the merits is to be given and claims rejected, the primary examiner may indicate how the references are to be applied in any prior art rejection and explain the basis for any non-prior art grounds of rejection. The primary examiner may authorize allowance if all statutory requirements are met and no further field of search is known.