In addition to the book Practical friendship
There are currently three papers out on friendship and capturing a common understanding of the concept.
This paper uses a dataset generated from keyword tagging works of literature and contemporary sources to scope the potential of a common definition and understanding of friendship. About 10000 keyword tags on about 300 keywords are used to extract friendship definitions from authors such as Aristotle, Cicero, C.S. Lewis, Alberoni, Nehamas, Greif, Degges-White, Hall, Shumway, Millington and others. On the compiled dataset MDS and correlational analysis is used to validate intuitive groupings and relatedness of friendship concepts. Six key dimensions of friendship are deduced with 55 subtraits.
This study revisits the topic of friendship dimensions and types, following on from Hall 2012. Data from 177 participants resulting in 477 friendship pairs are evaluated with clustering techniques. A group of base characteristics common to most friendship is observed, that subsequently splits out into different groups. The diversity in patterns may indicate that friendship standards are not universal even from the eye of the individual, but dependent on the assigned type or role.
This study investigates the quality of questions and labels used in friendship surveys. 113 participants generate 339 responses on 55 friendship traits which question or label is best suited to query for the respective trait. Overall past formulation choices can be shown to be reasonably robust.
I am also currently working on summarizing the habits survey at the foundation of the book into a short data paper.