Perhaps you should try some spelling variations:
"improving pupil performance metrics." » "improving pupil performance measures.", "improving social performance metrics.", "improving model performance metrics.", "improving judicial performance metrics.", "improving public performance metrics.", "improving civil performance metrics.", "improving audit performance metrics."
"improving bank performance series." » "improving bank performance studies.", "improving bank performance size.", "improving urban performance series.", "improving basic performance series.", "improving brain 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 bank performance series.") OR ("improving pupil performance metrics."))~.
• Removing quotes may allow a broader search: (( improving bank performance series. ) or ( improving pupil performance metrics. ))~.
• Adding a wildcard symbol may retrieve word variants: (("improving bank performance series.") or ("improving pupil performance metrics."))*.