Personalised Decision-Making without Counterfactuals
A. Philip Dawid, Stephen Senn
TL;DR
The paper challenges Mueller and Pearl's counterfactual, personalised decision-making framework by contrasting it with the traditional decision-theoretic approach. It formalises the MP perspective using potential outcomes, probabilities of benefit ${\rm PB}$ and harm ${\rm PH}$, and shows that exact identification is typically unattainable, with inference relying on interval bounds that can be narrowed under strong, often impractical assumptions. Through a detailed analysis, including the role of covariates, the concept of a preferred treatment (PT), and data fusion from experiments and observations, the authors demonstrate that, in general, decision theory yields clearer, more ethically defensible guidance and can, in special cases, match MP when PT is observed. They advocate exploiting PT within a decision-theoretic framework as a practical, robust alternative, cautioning against adopting counterfactual-based methods in routine practice. The work emphasizes realism about representativeness and the limits of data fusion, urging humility and careful consideration of clinical applicability.
Abstract
This article is a response to recent proposals by Pearl and others for a new approach to personalised treatment decisions, in contrast to the traditional one based on statistical decision theory. We argue that this approach is dangerously misguided and should not be used in practice.
