Coding motives reproducibly in mass murder datasets requires a structured, rule-based protocol with predefined categories, multiple coders for inter-rater reliability, and clear decision hierarchies to minimize subjectivity.[pmc.ncbi.nlm.nih]

Define Categories

Establish exhaustive, mutually exclusive motive classes upfront, such as psychosis (delusions/hallucinations), ideology (political/religious extremism), personal grievance (romantic rejection, grudges), rage (disputes), or despair (life events), mirroring analyses of 1,725 cases from 1900-2019. Prioritize primary motive via hierarchy: clinical evidence trumps manifestos; use subcategories for granularity (e.g., romantic vs. non-romantic grudge).[pmc.ncbi.nlm.nih]

Coding Protocol

Extract data from sources like manifestos, psych records, witness accounts, and media using standardized templates: note verbatim quotes, timestamps, and context. Assign codes blindly by independent raters (aim for Cohen’s kappa >0.8); resolve discrepancies via adjudication rounds with documented rationale. Automate initial passes with NLP keyword matching (e.g., “Allah” flags ideology), followed by manual verification.[arxiv +1]