Kappa Alpha Psi is a fraternity of students and alumni. There is a Wikipedia article in English, a Commons category and a Wikidata item.
The information about Kappa Alpha Psi at Wikidata is based on the Wikipedia article. Information was added to the items for the members. This was done because in a related item it was found that the influence of fraternities and sororities is considerable. Concentrating for a moment on Kappa Alpha Psi has a secondary quality impact on what is of primary concern but when this is done for three such organisations, it quickly affects thousands of notable people.
When people find it of interest to add information about a membership to a Wikipedia article it has some impact. Having a category helps more to make the relevance of a Kappa Alphi Psi more visible. Adding this information to Wikidata is easy and it may show up in any language when membership information is part of a template.
DBpedia is a project similar to Wikidata. It harvests data from Wikipedias more consistently than Wikidata. Wikidata items are mapped to its internal items making it is possible to compare Wikidata with DBpedia.
When quality is an objective, when quality is to be improved effectively, the differences between DBpedia and Wikidata are an easy and one of the more obvious starting points. For some Wikipedias DBpedia updates are based on the RSS feed of the changes. So once a difference has been curated and changed in either Wikipedia or Wikidata, it results in an improved DBpedia entry and the desired improvement in quality. It does not need any math to understand this.
What we needed is a tool that uses these differences as input for a subset that is of interest to a Wikidata volunteer. That might be the Kappa Alpha Psi, The Black Lunch Table or whatever. Whatever can be defined with a query.