ABSTRACT
From 1978 until 2012, the metric of cost per function point was used to aggregate as many as 60 different kinds of software work into a total cost of ownership (TCO) that used function points for data normalization. In 2012, International Function Point Users Group (IFPUG) introduced a new metric called software nonfunctional assessment process (SNAP). Before SNAP, nonfunctional requirements were still part of software development and had the effect of raising cost per function point. When SNAP metrics arrived in 2012, they were not designed to be mathematically equivalent to function points. Now the 2016 productivity for normal development would be 11.25 function points per month and the SNAP effort would be 7.50 SNAP points per month. Retrofitting SNAP to older software benchmarks is difficult and expensive. It is also expensive to integrate SNAP into commercial parametric estimation tools. Nonfunctional requirements seem to go up with size in function points.
