Being a critical edition of the Greek New Testament, the Nestle-Aland provides an eclectic text reconstructed from the tradition by means of a combination of external and internal criteria. The internal criteria are based on the intrinsic coherence of the text, its grammatical structure and its stylistic, linguistic and theological features. These cannot be applied without giving full weight to exegetical insights and studies. The external criteria are related to the quality and reliability of the witnesses supporting a variant. They are derived from the text-historical place and the transcriptional character of single witnesses and groups of witnesses.

Introduction to Novum Testamentum Graece (NA28)