Perhaps you should try some spelling variations:
"improving donor performance metrics." » "improving poor performance metrics.", "improving motor performance metrics.", "improving monitor performance metrics.", "improving indoor performance metrics.", "improving gender performance metrics.", "improving export performance metrics."
"improving food performance measures." » "improving good performance measures.", "improving fund performance measures.", "improving bond performance measures."

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

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