I had the opportunity to interview Fred Hasselman, the main architect of casnet: An R toolbox for studying Complex Adaptive Systems and NETworks. We spoke of how compatible the complex systems perspective is with some methods widely used in social sciences.

A few notes:

• Multilevel models (and what you put in those) come in many varieties – and some are useful
  • See this blog post for an overview of how multi-level survival model can be used to study early warning signals for clinical change.
  • Same strategy used in physical activity research in a recent preprint of ours (includes data and code): Characterizing and predicting person-specific, day-to-day, fluctuations in walking behavior
• Interaction is not interaction
  • Interaction (1): Two variables are intertwined – or “coupled” – in such a way, that they cannot be separated without severing the phenomena arising from their interplay.
  • Interaction (2): A multiplicative, instead of additive, relationship in a linear regression model, where you can partial out variance and get nice beta weights for each variable to determine their individual impacts.
  • The two meanings presented above are logically inconsistent: See #36 in Scott Lilienfield’s “Fifty psychological and psychiatric terms to avoid“
    • See also this piece: On the distinction between interaction and effect modification
• Interdependence means you can’t use the regular statistics which social scientists know and love.
  • … because you lose additivity.
• “Don’t infer causality, observe it.”
  • When the system you’re looking at is an individual instead of e.g. the society, you’re in the quite happy position, that lab studies are possible (if you’re smart about them).
• An excellent paper from Merljin Olthof: Complexity in psychological self-ratings: implications for research and practice
• Additional resources:
  • A symposium we held on complexity in behavioural science, evidence and policy.
  • A workshop by Fred Hasselman (scroll to the end for an extensive reading list).
  • University of Helsinki course by Matti: CARMA – Critical Appraisal of Research Methods and Analysis.

Because every post needs an image, here’s Julia Rohrer‘s (2017) Theory of Regulation of Empty Theories (TROETE)