Perhaps you should try some spelling variations:
"improving job performance metrics." » "improving job performance measures.", "improving court performance metrics.", "improving co performance metrics.", "improving food performance metrics.", "improving crop performance metrics."
"improving trade performance series." » "improving trade performance studies.", "improving trade performance size.", "improving care performance series.", "improving tax performance series.", "improving teacher performance series."

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

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