Classification Model Bias Correction via Record Perturbation

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Solution Overview

Problem

Existing classification models face challenges in accurately determining bias and fairness, as current metrics may not be effective across various scenarios, leading to potential unfair treatment of different groups.

Innovation Solution

A method that involves perturbing original records to generate perturbed records, calculating confidence values for both, determining a final confidence value using the direction of distance traveled, and re-training the model based on biased records to correct bias, utilizing a computer-implemented system to assess and improve model fairness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing fairness metrics (parity metric, equality of opportunity metric, equality of odds metric, bounded error loss metric) are used to measure classification model fairness, then the model behavior can be evaluated, but the metrics are not accurate across different scenarios

Engineering Contradiction:
Improvefairness measurement accuracyVSAvoidmetric applicability across scenarios
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameters used for fairness measurement from traditional metrics (parity, equality of opportunity, equality of odds, bounded error loss) to a new parameter based on confidence value differences. This parameter change enables accurate fairness assessment across different scenarios by focusing on how confidence values change when protected attributes are modified, rather than relying on scenario-specific metric definitions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a universal fairness measurement approach that works across all classification scenarios by using confidence value differences as a common metric. The method can evaluate fairness for any classification model and any protected attribute (race, gender, age, etc.) without requiring scenario-specific metric selection, making it universally applicable

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If traditional fairness metrics are applied to determine model bias, then model behavior can be analyzed, but the determination of bias is not accurate

Engineering Contradiction:
Improvebias determination accuracyVSAvoidcomplexity of fairness assessment system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates perturbed copies of original data records by modifying protected attributes (e.g., changing race from 'white' to 'black', or gender from 'male' to 'female'). These copied records with altered protected attributes are then processed through the classification model to measure confidence value differences, providing a reliable and straightforward method for bias determination without complex analytical systems

Inventive Principle:
Principle #26Copying

3Measurement precision

If confidence value differences are measured to determine bias, then accurate fairness assessment is achieved, but the computational process becomes more complex

Engineering Contradiction:
Improvefairness measurement accuracyVSAvoidcomplexity of perturbation and confidence calculation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The classification model serves itself by processing both original and perturbed records through the same model infrastructure. The system leverages the model's own confidence output mechanism to measure fairness, requiring no external fairness assessment tools or complex additional computational systems - the model's existing confidence calculation capability is repurposed for fairness measurement

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20240249187A1Correcting a classification model
Publication Date: 2024.07.25 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US20240249187A1 patent drawing
  • US20240249187A1 patent drawing
  • US20240249187A1 patent drawing

AI summary

Provided are techniques for correcting a classification model. For each original record of a plurality of original records that are processed by a classification model: the original record is perturbed; for the original record, an original confidence value is obtained for each class of a plurality of classes; for the perturbed record, a perturbed confidence value is obtained for each class of the plurality of classes; a final confidence value is determined using each original confidence value, each perturbed confidence value, and a direction of distance travelled; and a determination is made of whether the original record is biased based on the final confidence value. Then, it is determined whether the classification model is biased based on the original records that are determined to be biased. In response to determining that the classification model is biased, the classification model is corrected, otherwise, the classification model is deployed.