Perhaps you should try some spelling variations:
"improving contract performance measures." » "improving country performance measures.", "improving court performance measures.", "improving economic performance measures.", "improve contract performance measures.", "improving central performance measures.", "improve contrast performance measures."
"improving level performance based." » "improving model performance based.", "improving revenue performance based.", "improving pupil performance based.", "improving legal performance based.", "improving lives performance based.", "improving local performance based."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving contract performance measures.") or ("improving level performance based."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving contract performance measures.") OR ("improving level performance based.")).
• Removing quotes may allow a broader search: (( improving contract performance measures. ) or ( improving level performance based. )).
• Adding a wildcard symbol may retrieve word variants: (("improving contract performance measures.") or ("improving level performance based."))*.