Introduction

FairGrad, is an easy to use general purpose approach to enforce fairness for gradient descent based methods. The core idea is to enforce fairness by iteratively learns group specific weights based on whether they are advantaged or not. FairGrad is:

  • Simple and easy to integrate with no significant overhead

  • Supports Multiclass problems and can work with any gradient based methods

  • Supports various group fairness notions including exact and approximate fairness

  • Is competitive on various tasks including complex NLP and CV ones

Installation

You can install FairGrad from PyPI with pip or your favorite package manager:

pip install fairgrad

Quick Start

To use fairgrad simply replace your pytorch cross entropy loss with fairgrad cross entropy loss. Alongside, regular pytorch cross entropy arguments, it expects following extra arguments:

y_train (np.asarray[int], Tensor, optional): All train example's corresponding label.
         Note that the label space must start from 0.
s_train (np.asarray[int], Tensor, optional): All train example's corresponding sensitive attribute. This means if there
        are 2 sensitive attributes, with each of them being binary. For instance gender - (male and female) and
        age (above 45, below 45). Total unique sentive attributes are 4.
        Note that the protected space must start from 0.
fairness_measure (string): Currently we support "equal_odds", "equal_opportunity", "accuracy_parity", and "demographic_parity".
                           Note that demographic parity is only supported for binary case.
epsilon (float, optional): The slack which is allowed for the final fairness level.
fairness_rate (float, optional): Parameter which intertwines current fairness weights with sum of previous fairness rates.

Usage Example

Below is a simple example:

>>> from fairgrad.torch import CrossEntropyLoss
>>> input = torch.randn(10, 5, requires_grad=True)
>>> target = torch.empty(10, dtype=torch.long).random_(2)
>>> s = torch.empty(10, dtype=torch.long).random_(2) # protected attribute
>>> loss = CrossEntropyLoss(y_train = target, s_train = s, fairness_measure = 'equal_odds')
>>> output = loss(input, target, s, mode='train')
>>> output.backward()

For complete worked out example refer to example folder on github.

We highly recommend to standardize features by removing the mean and scaling to unit variance. This can be done using standard scalar module in sklearn.

Citation

Citation for this work:

@article{maheshwari2022fairgrad,
          title={FairGrad: Fairness Aware Gradient Descent},
          author={Maheshwari, Gaurav and Perrot, Micha{\"e}l},
          journal={arXiv preprint arXiv:2206.10923},
          year={2022}}