NSCA estimates necessity with the NCA engine and sufficiency with SCAtools. Please cite NSCA, the two packages it delegates to, and the underlying NCA method.

Chan Y (2026). NSCA: Necessary and Sufficient Condition Analysis. R package version 0.4.5.

Chan Y (2026). SCAtools: Direction-Aware Sufficiency Condition Analysis. R package.

Dul J (2016). “Necessary Condition Analysis (NCA): Logic and Methodology of 'Necessary but Not Sufficient' Causality.” Organizational Research Methods, 19(1), 10–52. doi:10.1177/1094428115584005.

Corresponding BibTeX entries:

  @Manual{,
    title = {NSCA: Necessary and Sufficient Condition Analysis},
    author = {Young Chan},
    year = {2026},
    note = {R package version 0.4.5},
  }

  @Manual{,
    title = {SCAtools: Direction-Aware Sufficiency Condition Analysis},
    author = {Young Chan},
    year = {2026},
    note = {R package},
  }

  @Article{,
    title = {Necessary Condition Analysis (NCA): Logic and Methodology
      of 'Necessary but Not Sufficient' Causality},
    author = {Jan Dul},
    journal = {Organizational Research Methods},
    year = {2016},
    volume = {19},
    number = {1},
    pages = {10--52},
    doi = {10.1177/1094428115584005},
  }