Several documents describe various sources of data used in SkillTRAN products. Not all products contain all of these data sources.
Government Data Sources Used In SkillTRAN Products (2020)
Occupational Requirements Survey (2020)
Social Security Memo recognizing SkillTRAN products as an acceptable electronic version of the DOT (2009)
Public Systems Where the DOT is Primarily Used (2012 - by Mary Barros Bailey, Ph.D.)