Perhaps you should try some spelling variations:
"improving coverage performance series." » "improving average performance series.", "improving overall performance series.", "improving governance performance series.", "improved coverage performance series.", "improves coverage performance series.", "improving coverage performance studies.", "improving coverage performance size."
"improving social performance metrics." » "improving social performance measures.", "improving school performance metrics.", "improving fiscal performance metrics.", "improving financial performance metrics."

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

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