Automated comparison of Darwin Information Typing Architecture (DITA) documents for revision mark-up includes reading document data from first and second DITA documents into respective document object model trees of nodes, and identifying and collapsing emphasis subtree nodes in the trees into their parent nodes, the collapsing caching emphasis data from the identified subtree nodes. A traversal transforms the model trees into respective node lists and captures adjacent sibling emphasis subtree nodes as single text nodes. The node lists are merged into a merged node list that recognizes matches node pairs having primary sort key information and document structure metadata meeting a match threshold, with differences between matching tokens of the node pairs saved. A merged document object model built from the refined merged node list is transformed into a hypertext mark-up language document.