The Nail Psoriasis Severity Index (NAPSI) is a numeric, reproducible, objective, simple tool for evaluation of nail psoriasis.  It evaluates several signs separately, each on a 1–3 scale: pitting, Beau's lines , subungual hyperkeratosis and onycholysis . A 2005 study proposed a modified NAPSI scale for persons with psoriasis and named the title of their publication "Modification of the Nail Psoriasis Severity Index".  Then, in 2007, a study found that there was a high level of inter-rater variability of the 2003 NAPSI scale and proposed another index which was, like the 2005 article, a modification of the 2003 article, and was named modified NAPSI.  A 2008 study found that Cannavo's qualitative system  correlated with NAPSI (P<) and is less time-consuming.