HiScore author here. HiScore allows domain experts to easily create and maintain scores. It is currently being used by a major environmental non-profit and by IES, a startup that assesses the safety and sustainability of fracking wells.

The algorithm itself is a mashup of a paper I wrote for AAAI: http://www.cs.cmu.edu/~aothman/splines.pdf and this paper: http://link.springer.com/article/10.1007/s10543-005-0028-x

Asker of the StackOverflow question here! (And payer of the 500-point bounty to the author of HiScore, which I think is brilliant!) I'm excited about this for the potential applications for personal (or startup) goal tracking, like turning a bunch of constituent numbers into a single metric for how well you're doing.