Perhaps you should try some spelling variations:
"improving firm performance review." » "improving firm performance risk.", "improving firm performance evidence.", "improving _ performance review.", "improving firms performance review.", "improving air performance review.", "improving birth performance review."
"improving public performance review." » "improving public performance risk.", "improving public performance evidence.", "improving building performance review.", "improving specific performance review.", "improving quality performance review."

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

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