Causal inference without graphs

In a recent posting on this blog, Elias and Bryant described how graphical methods can help decide if a pseudo-randomized variable, Z, qualifies as an instrumental variable, namely, if it satisfies the exogeneity and exclusion requirements associated...

A Crash Course in Good and Bad Control

Carlos Cinelli, Andrew Forney and Judea Pearl Introduction If you were trained in traditional regression pedagogy, chances are that you have heard about the problem of “bad controls”. The problem arises when we need to decide whether the addition...

Lord’s Paradox: The Power of Causal Thinking

Background This post aims to provide further insight to readers of “Book of Why” (BOW) (Pearl and Mackenzie, 2018) on Lord’s paradox and the simple way this decades-old paradox was resolved when cast in causal language. To recap, Lord’s paradox...

Graphical Models and Instrumental Variables

At the request of readers, we re-post below a previous comment from Bryant and Elias (2014) concerning the use of graphical models for determining whether a variable is a valid IV. Dear Conrad,Following your exchange with Judea, we would like to present...

CAUSAL INFERENCE SUMMER SHORT COURSE AT HARVARD

We are informed of the following short course  at Harvard. Readers of this blog will probably wonder what this Harvard-specific jargon is all about, and whether it has a straightforward translation into Structural Causal Models. It has! And one of...

On Imbens’s Comparison of Two Approaches to Empirical Economics

Many readers have asked for my reaction to Guido Imbens’s recent paper, titled, “Potential Outcome and Directed Acyclic Graph Approaches to Causality: Relevance for Empirical Practice in Economics,” arXiv.19071v1 [stat.ME] 16 Jul 2019. The note...

Generalizing Experimental Results by Leveraging Knowledge of Mechanisms

In a recent post (and papers), Anders Huitfeldt and co-authors have discussed ways of achieving external validity in the presence of “effect heterogeneity.” These results are not immediately inferable using a standard (non-parametric) selection...

Fréchet Inequalities – Visualization, Applications, and History

Scott Mueller and Judea Pearl This post introduces readers to Fréchet inequalities using modern visualization techniques and discusses their applications and their fascinating history. Table of Contents Introduction Plots Examples Example 1 Example...

Which Patients are in Greater Need: A counterfactual analysis with reflections on COVID-19

Scott Mueller and Judea Pearl With COVID-19 among us, our thoughts naturally lead to people in greatest need of treatment (or test) and the scarcity of hospital beds and equipment necessary to treat those people. What does “in greatest need” mean?...