Concern for others — that’s something to think about (13)
I believe the answer is:
consideration
I believe this is a double definition.
'concern for others' is the first definition.
(being considerate of other people)
'something to think about' is the second definition.
(a matter or detail requiring special consideration)
'that's' acts as a link.
(Other definitions for consideration that I've seen before include "Study" , "Kindness" , "Bearing in mind - payment" , "Reward; careful thought" , "factor to be borne in mind" .)