Perhaps you should try some spelling variations:
"improving school performance metrics." » "improving school performance contracts.", "improving school performance measures.", "improving school performance contract.", "improving schools performance metrics.", "improving preschool performance metrics.", "improve school performance metrics."
"improving human performance series." » "improving human performance reviews.", "improving human performance review.", "improving human performance targets.", "improving loan performance series.", "improving thermal performance series.", "improving company performance series.", "improving urban performance series.", "improving rural performance series."

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 human performance series.") or ("improving school performance metrics."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving human performance series.") OR ("improving school performance metrics.")).
• Removing quotes may allow a broader search: (( improving human performance series. ) or ( improving school performance metrics. )).
• Adding a wildcard symbol may retrieve word variants: (("improving human performance series.") or ("improving school performance metrics."))*.