This blog post is part of a series on storing uncertain data in nodegoat: 'How to store uncertain data in nodegoat', 'Incomplete source material', 'Conflicting information', 'Ambiguous identities'.

You are often confronted with omissions or with inconclusive statements when you deal with historical source material. To let your dataset reflect the nature of your sources, it is important that you include these vague or uncertain statements in your data. This blog post will go over a number of strategies that will help you to deal with these cases in your nodegoat project.

A common scenario is a case where you lack information. When this happens, you can decide to leave a given description, date, or location empty. This gives you the ability to create a filter that finds the objects that have empty descriptions, dates, or locations.

In another situation you might encounter a source that is partially lacking. The source does provide you with some information, but is inconclusive about the certainty of the information. An example of this is the entry on John Chamberlayne in the Dictionary of National Biography:

Leslie Stephen, Dictionary of National Biography, v. 10 (Elder Smith & Co., 1887), page 9. Available at wikisource.

The first sentence of his entry reads: "CHAMBERLAYNE, JOHN (1666–1723), miscellaneous writer, a younger son of Edward Chamberlayne [q. v.], was born about 1666, probably in or near London."

We will discuss four strategies for accommodating this uncertain source: a true/false statement on certainty, a scale on the level of certainty, entering chronology statements, and entering geometries.[....]