Perhaps you should try some spelling variations:
"improving human performance metrics." » "improving human performance measures.", "improving human performance contract.", "improving loan performance metrics.", "improving thermal performance metrics.", "improving company performance metrics.", "improving urban performance metrics.", "improving rural performance metrics."
"improving mental performance contracts." » "improving senegal performance contracts.", "improving annual performance contracts.", "improving entry performance contracts.", "improving maternal performance contracts.", "improving social performance contracts.", "improving rural performance contracts."

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

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