Disentangled Representation Learning for Temporal Causal Inference

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Solution Overview

Problem

Existing techniques for temporal causal inference face challenges in accurately predicting future treatment effects due to time-varying confounders, which are often treated as fully confounding, leading to inefficiencies in balancing representations and high variance in predictions, especially in medical decision-making scenarios where standard randomized control trials are impractical.

Innovation Solution

The proposed system, Disentangled Representations for Temporal Causal Inference (DRTCI), uses a recurrent neural network with LSTM units to learn disentangled representations of patient covariates, separating them into outcome, confounding, and treatment representations, allowing for more precise prediction of future outcomes and treatment assignments by isolating confounding factors and reducing unnecessary balancing efforts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If time-varying confounders are treated as fully confounding to balance representations, then bias in outcome prediction is reduced, but variance increases and representation efficiency decreases

Engineering Contradiction:
Improvebias reduction in outcome predictionVSAvoidprediction variance
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the confounder representation into two distinct components: a confounding representation (ΦΔ) that captures time-varying confounders affecting treatment assignment, and an outcome representation (Φγ) that captures factors influencing outcomes. This segmentation allows selective balancing of only the confounding component while preserving outcome-predictive information, thereby reducing bias without increasing variance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by treating different components of the covariate representation differently: the confounding representation is balanced across treatment groups while the outcome representation is preserved for prediction. This localized treatment of different representation components optimizes both bias reduction and variance control.

Inventive Principle:
Principle #3Local quality

2Reliability

If all time-varying covariates are balanced to eliminate confounding, then causal inference accuracy improves, but information about future outcomes is lost

Engineering Contradiction:
Improvecausal inference accuracyVSAvoidoutcome-predictive information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the covariate representation into confounding and outcome components, allowing differential processing: confounding representation is balanced for causal inference while outcome representation is preserved for prediction, preventing information loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different quality standards to different parts of the representation: the confounding representation undergoes balancing to ensure causal accuracy, while the outcome representation maintains its predictive information without balancing, thus avoiding information loss.

Inventive Principle:
Principle #3Local quality

3Reliability

If standard randomized control trials are conducted for every temporal variation, then treatment evaluation reliability is maximized, but feasibility and cost increase significantly

Engineering Contradiction:
Improvetreatment evaluation reliabilityVSAvoidtrial feasibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent creates a computational model (counterfactual recurrent network) that copies and simulates the effects of randomized control trials through learned representations and reweighting mechanisms, eliminating the need for actual trials for every temporal variation while maintaining reliable treatment evaluation.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical system of conducting actual randomized control trials with a computational system that uses learned representations, propensity score reweighting, and counterfactual prediction to achieve the same evaluation goals more efficiently.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If existing recurrent models use hidden representations to balance time-varying confounders, then confounding bias is reduced, but representation of covariates influencing both treatment and outcome is curtailed

Engineering Contradiction:
Improveconfounding bias reductionVSAvoidcovariate representation
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the hidden representation into distinct confounding and outcome components, allowing the confounding component to be balanced while the outcome component preserves full covariate information, thus avoiding curtailment of useful representations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing quality to different representation components: confounding representation is balanced to reduce bias while outcome representation is preserved to maintain information, resolving the contradiction between bias reduction and information preservation.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS12051507B2System and method for learning disentangled representations for temporal casual inference
Publication Date: 2024.07.30 TATA CONSULTANCY SERVICES LTD
  • US12051507B2 patent drawing
  • US12051507B2 patent drawing
  • US12051507B2 patent drawing

AI summary

Existing techniques assume that all time varying covariates are confounding and thus attempts to balance a full state representation of a plurality of historical observants. The present disclosure processes a plurality of historical observants and treatment at a timestep t specific to each patient using an encoder network to a obtain a state representation st. A first set of disentangled representations comprising an outcome, a confounding and a treatment representation is learnt to predict an outcome t+1. The first set of disentangled representations are concatenated to obtain a unified representation and the decoder network is initialized using the unified representation to obtain a state representation st+1. A second set of disentangled representations is learnt and concatenated to predict outcome t+m+1 m+1 timesteps ahead of the timestep t and proceeding iteratively until m=τ−1.