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."
"improve basic performance series." » "improve basic performance studies.", "improve basic performance size.", "improve based performance series.", "improve music performance series.", "improve baseline 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: (("improve basic performance series.") or ("improving pupil performance metrics."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improve basic performance series.") OR ("improving pupil performance metrics.")).
• Removing quotes may allow a broader search: (( improve basic performance series. ) or ( improving pupil performance metrics. )).
• Adding a wildcard symbol may retrieve word variants: (("improve basic performance series.") or ("improving pupil performance metrics."))*.