These are the guidelines for the ERRATAS project for charting editorial interference in edited collections of English historical correspondence. This checklist is to be used when going through the corpus texts and source editions of CEEC-400 collections, and feeding information into the ERRATAS database in MS Access. This document contains information on the various features to be charted, on what kind of information is to be recorded, and on the data type of this information. The checklist below also contains audit word lists – that is, lists of words exhibiting the feature in question, which can be used to query the corpus collections to see what the editor has done with that feature. UPDATE 14.4.2023: A final version of this checklist has been released. It is included in the bundle of the latest upload of the ERRATAS database of editorial principles and practices in printed editions of historical correspondence. This document has now been superseded, but it still applies to the earlier release of the ERRATAS database.