The eXtensible Markup Language (XML) is a data set to represent data in a format that is both human readable and machine readable. For XML documents to provide understanding about data exchange between applications, XML schema documents should be validated against the schema language. Most existing schema metrics were implemented differently in Document Type Definition (DTD), XML Schema Definition (XSD) and Regular Language for Next Generation (RNG) but never compare XML schema languages on any metric. Hence this paper compared three different schema languages on Improved Entropy Metric (IEM) using the Number of Attributes (NA), Number of Equivalence Class (NEC), Frequency Occurrence of Class (FOCi) and Number of Elements (NE). The proposed...