 The original data sample consisted of 66 firms, half of which had filed for bankruptcy under Chapter 7.All businesses in the database were manufacturers, and small firms with assets of realequityresearch.dk/Documents/Z-Score_Altman_1968.pdf

Altman found that the ratio profile for the bankrupt group fell at −0.25 avg, and for the non-bankrupt group at +4.48 avg.Altman's work built upon research by accounting researcher William Beaver and others.