Primer for building factor trees to represent social-science knowledge

Factor trees are relatively simple causal diagrams that indicate the many factors contributing to a phenomenon or effect at a snapshot in time. They consist of nodes and directional arcs (arrows) arranged in nearly hierarchical layers so that the effect can be seen as depending on a few high-level factors, but with those depending in turn on more detailed factors. This paper is a primer on building general and context-specialized factor trees; it includes subtleties and admonitions based on experience in several recent integrative studies on social science knowledge relating to terrorism, public support of insurgency and terrorism, and stabilization and reconstruction. It also discusses experiences with efforts to validate such conceptual models. Finally, the paper notes limitations and suggests supplementary methods.