If I remember correctly this article describes some considerations and metrics: https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.108.1711&rep=rep1&type

If I remember correctly this article describes some considerations and metrics: https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.108.1711&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10... (it has been a while since I read it though)