Perhaps you should try some spelling variations:
"improving macro performance metrics." » "improving macro performance measures.", "improving crop performance metrics.", "improving ceo performance metrics.", "improving machine performance metrics.", "improving air performance metrics.", "improving care performance metrics.", "improving co performance metrics."
"improving upper performance series." » "improving upper performance studies.", "improving upper performance size.", "improving under performance series.", "improving support performance series.", "improving capped performance series.", "improving supply performance series.", "improving budget performance series.", "improving gender performance series."

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

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