Perhaps you should try some spelling variations:
"improving social performance reviews." » "improving social performance review.", "improving social performance reports.", "improving social performance risks.", "improving school performance reviews.", "improving fiscal performance reviews.", "improving financial performance reviews."
"improving public performance series." » "improving music performance series.", "improving policy performance series.", "improving public performance studies.", "improving public performance size."

Try widening your search to All Fields.

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

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