The Collaborative International Dictionary of English v.0.48:

Productivity \Pro`duc*tiv"i*ty\, n.
   The quality or state of being productive; productiveness.
   --Emerson.
   [1913 Webster]

         Not indeed as the product, but as the producing power,
         the productivity.                        --Coleridge.
   [1913 Webster]

WordNet (r) 3.0 (2006):

productivity
    n 1: the quality of being productive or having the power to
         produce [syn: productiveness, productivity] [ant:
         unproductiveness]
    2: (economics) the ratio of the quantity and quality of units
       produced to the labor per unit of time