Coherence and cohesion are dimensions within overall article development that deal with how text and other information is organized and structured within an article and how different articles are organized and linked to form a more complete picture - concepts that we will be dealing with more and more as new article creation slows down due to our approaching a theoretical concept limit. With over 5 M articles as of November 2015, there are fewer missing articles to write in many areas (although gender bias in Wikipedia and racial bias in Wikipedia have left significant gaps in topics pertaining to women and people of colour). This means that in many subject areas, our editing work will take a greater focus on developing existing articles and topics to their maximum depth and ensuring that existing articles are well-linked and connected together through the use of wikilinks, categories, topicboxes, "see also" sections and other techniques.
There are areas which are well developed: Well formed articles are considered such largely because they deal with and link to the most relevant superordinate (contexts) and subordinate topics (concepts) in a logical order. The liberal usage of topicboxes is a necessity for large series of articles to be coherently navigable and developed.
Coherency refers to an article providing logical, understandable and usable knowledge to the reader. In order to be coherent,
|1||the article shall treat one topic, or many topics that are logically related to each other,||otherwise the article is fragmented|
|2||if many topics are treated, then there shall be text that relates each topic to each other,||otherwise the article is fragmented|
|3||the language shall be as easy, straightforward and jargon-free as possible, not making outright deviations from the topic before reaching an explanation, and||otherwise the language is messy and/or unclear|
|4||the terms should be as common, as unambiguous and as comprehensible as possible, the terms used mustn't contradict each other,||otherwise the language contains too much jargon and will be hard to understand|
|5||the article layout shall follow, in most cases, the conventional article section order in Wikipedia,||because this makes it easier for readers to navigate around a new article,|
|6||and the article shall neatly integrate, (not contradict, not overlap), into the larger dataset called Wikipedia.||coherency on a larger scale|
Coherency is not about truth and verification. Coherency is about understandability, clarity and logic. If there is neither too much nor too little information, and the explanation is simple and clear, instead of overflowing with irrelevant details, then the article is coherent!