Perhaps you should try some spelling variations:
"improving voluntary performance evidence." » "improving country performance evidence.", "improving entry performance evidence.", "improving budgetary performance evidence."
"improving basic performance targets." » "improving based performance targets.", "improving bank performance targets.", "improving past performance targets.", "improving air performance targets.", "improve basic performance targets.", "improving public performance targets."

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

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