Economy by good people shows redeeming quality (6,5)
I believe the answer is:
saving grace
'redeeming quality' is the definition.
(a redeeming quality or feature)
'economy by good people' is the wordplay.
'economy' becomes 'saving' (synonyms).
'by' means one lot of letters go next to another.
'good' becomes 'g' (abbreviation).
'people' becomes 'race' (people can mean a national group or race).
'saving'+'g'+'race'='SAVING GRACE'
'shows' is the link.
(Other definitions for saving grace that I've seen before include "Redeeming quality" , "Redeeming feature" , "a description of Miss Darling?" , "What stops one condemning" , "Compensatory good point" .)