Contributing element (6)
I believe the answer is:
factor
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">contributing element</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for factor that I've seen before include "Influencing circumstance" , "something that may affect result" , "Component, element" , "Circumstance that contributes towards a result" , "Reason" .)