AI Security

Understanding and Addressing Biases in Machine Learning


ML enables computers to learn from data and make decisions, facilitating applications from movie recommendations to medical diagnoses. It’s a key driver of innovation and is instrumental in advancing various fields, offering solutions to complex problems, and delivering personalized user experiences.

Overview of Biases in ML and Concerns

While ML offers extensive benefits, it also presents significant challenges, among them, one of the most prominent ones is biases in ML models. Bias in ML refers to systematic errors or influences in a model’s predictions that lead to unequal treatment of different groups. These biases are problematic as they can reinforce existing inequalities and unfair practices, translating to real-world consequences like discriminatory hiring or unequal law enforcement, thus creating environments of injustice and inequality.

The Importance of Addressing and Monitoring Biases Continuously

Given the evolving nature of ML models, it’s critical to monitor and address biases continuously. Addressing biases is both a technical and moral imperative to ensure that ML is equitable and inclusive. Ongoing efforts to understand and mitigate biases are essential, involving a collective responsibility among developers, users, and policymakers, in order to maintain the transparency, fairness, and accountability of AI systems.

Understanding ML Biases

Explanation of Bias in ML

Bias in ML can fundamentally be categorized into Pre-existing Bias, Technical Bias, and Emergent Bias:

Pre-existing Bias: This arises from underlying social and structural inequalities or prejudices in the environment, impacting the data collected for model training. For instance, if historical hiring data exhibit gender bias, a model trained on this data will likely perpetuate this bias in its predictions.

Technical Bias: This arises due to the limitations or characteristics of the algorithms or the data used for model training. For example, an image recognition model might exhibit lower accuracy for dark-skinned individuals if the training data predominantly contains images of light-skinned individuals.

Emergent Bias: This occurs when models learn and adapt to new data during use, causing the system to develop biases over time. For example, a natural language processing model might exhibit biases present in user-generated content that it processes and learns from, such as social media posts or articles.

Types of biases

Data Bias: Data Bias occurs when the dataset used to train the model is not representative of the population it serves, leading to imbalances. For instance, if a healthcare model is trained predominantly on data from one demographic group, its predictions may be inaccurate for other demographic groups.

Algorithmic Bias: Algorithmic Bias emerges when the algorithm’s design or its decision-making process introduces biases, often inadvertently. For example, a credit scoring model might assign more weight to certain features like zip codes, inadvertently favoring or disadvantaging individuals from certain areas.

Simplified Examples: Data and algorithmic biases are significant issues in machine learning models, illustrated by the following examples. A facial recognition system trained mainly with images of light-skinned individuals may inaccurately recognize individuals with darker skin tones, showcasing data bias due to unrepresentative training data. Additionally, a job recommendation engine that prioritizes programming language proficiency over other skills may overlook candidates who excel in other areas, depicting algorithmic bias where certain features are disproportionately valued. These examples underscore the imperative to address biases in developing fair and equitable machine learning models.

Historical Context and Real-world Incidents

The historical progression of ML models has been impacted by instances of ingrained biases leading to discriminatory and unjust outcomes, emblematic of broader, pre-existing societal inequalities. For instance, notable instances of gender bias in recruitment algorithms have surfaced, where models trained on historically biased data have systematically favored male candidates over equally or more qualified female candidates, reflecting and amplifying entrenched gender disparities in professional settings. Moreover, the deployment of facial recognition software has revealed profound racial biases, with systems exhibiting higher error rates for individuals with darker skin tones due to the underrepresentation of diverse racial groups in training datasets. These biased models don’t merely operate in vacuums; they have far-reaching repercussions on individuals and societies, perpetuating stereotypes, infringing upon individual rights, and engendering mistrust in technological advancements. The impact is multifaceted, affecting job prospects, societal inclusion, and equal treatment under law and services, thereby necessitating urgent rectification and preventive measures to curtail the propagation of such biases and foster the development of equitable and just ML models.

How Biases Enter ML Systems

Bias can infiltrate ML systems at various developmental stages, each one posing a unique challenge and requiring meticulous attention to ensure fairness and equity in model outcomes.

Data Collection

This initial stage is pivotal as it lays the foundation upon which models are built. Bias can be introduced here if the collected data is not representative of the diverse populations the model will serve or if it contains inherent biases reflecting pre-existing inequalities in society. In essence, non-representative or skewed data can shape the model’s understanding and subsequent predictions, perpetuating and potentially exacerbating underlying biases.

Example: Consider the development of a credit scoring model. If the initial data collection primarily includes financial information from affluent neighborhoods, the model might develop a skewed understanding of financial reliability, potentially disadvantaging applicants from less affluent backgrounds.

Model Training

Once data is collected, models are trained to learn patterns and make predictions. At this stage, bias can be introduced through the algorithm’s design or through biased training data. An algorithm’s sensitivity to certain features or its inability to comprehend complex relationships can lead to biased learning, particularly when trained on skewed data, resulting in discriminatory or unfair model predictions.

Example: Take an image recognition model trained predominantly on pictures of light-skinned individuals. The model, learning from this non-diverse dataset, is likely to exhibit lower accuracy when identifying individuals with darker skin tones, illustrating the introduction of bias during the training phase due to non-representative data.

Model Deployment

The final deployment of models in real-world scenarios is another juncture where biases can manifest. Even if a model is trained with unbiased data and algorithms, its interaction with real-world data and dynamic environments can lead to the emergence of new biases or the reinforcement of existing ones, affecting the model’s fairness and accuracy in unforeseen ways.

Example: Envision a language translation model deployed in dynamic, multilingual online platforms. If users predominantly interact with the model in a specific set of languages, the model might prioritize learning and optimizing for those languages over time, potentially undermining its performance in other languages and showcasing emergent bias during deployment.

The Responsibility to Address Biases

Addressing biases in ML is a shared, ethical responsibility with significant implications. Biased models risk perpetuating discriminatory outcomes and inequalities, necessitating vigilance and ethical consideration from developers, companies, and end-users. Developers are central in integrating fairness from conception to deployment; companies must foster ethical, transparent, and inclusive AI development environments, and end-users, along with the broader society, should advocate for equitable AI systems. The dynamic and evolving nature of AI also underscores the need for continuous monitoring and adaptation to mitigate emerging biases and ensure ongoing fairness and equity in ML models. This convergence of ethical diligence and technical refinement is crucial to steer the development and deployment of AI systems towards a more equitable, inclusive, and socially beneficial trajectory.

Strategies for Addressing and Monitoring Biases

Fairness in ML and Ethical AI

Achieving fairness in ML is critical in the development of ethical AI systems. It involves recognizing and addressing biases in every development stage, ensuring models produce equitable, unbiased, and inclusive results. The commitment to fairness and ethical AI necessitates a holistic approach, integrating ethical considerations and values into the AI development process, thus fostering the creation of AI systems that respect human rights and values and contribute positively to society.

Bias Detection Techniques

Detecting biases is a crucial step in building fair AI systems. Fairness indicators offer quantitative ways to measure model performance across diverse groups, identifying disparities in model predictions, while various model evaluation techniques, including confusion matrices and ROC curves, allow for comprehensive assessments of models’ fairness and biases. These techniques enable developers to uncover implicit, unintended biases, allowing for informed adjustments and refinements to address identified disparities, thereby contributing to the enhancement of model fairness and the reduction of harmful biases.

Mitigation Strategies

Once biases are detected, employing mitigation strategies is essential. Data augmentation involves expanding and balancing training datasets by adding more diverse and representative samples, helping models to generalize better across varied inputs. Meanwhile, algorithmic debiasing techniques aim to modify algorithms to reduce the impact of biases in model predictions, enhancing fairness in model outcomes. These strategies, when properly implemented, can significantly mitigate the influence of biases in ML models, ensuring more equitable, inclusive, and unbiased AI systems.

Tools and Resources for Monitoring Biases

In the pursuit of ethical AI, a number of tools and frameworks are available to assist in detecting, monitoring, and addressing biases in ML. These include platforms like IBM’s AI Fairness 360, Google’s What-If Tool, and Fairlearn, offering extensive functionalities to evaluate and mitigate biases in models across varied contexts. These tools are complemented by a myriad of community-driven efforts and initiatives aimed at fostering the development and deployment of ethical and unbiased AI, such as Partnership on AI and AI for People, which work collaboratively to address challenges and set standards in AI ethics. To empower individuals in contributing to this ethical AI landscape, a wealth of online resources, workshops, and courses are accessible, providing insights and knowledge on AI ethics, bias mitigation strategies, and responsible AI practices. Such resources cultivate awareness and proficiency, enabling a diverse array of stakeholders to engage meaningfully in the discourse on ethical AI and actively participate in shaping an equitable and unbiased AI-driven future.

Recent Research on ML Biases

Recent research underscores the multifaceted nature of biases in Machine Learning (ML) and explores various dimensions and implications of biases in AI. For instance, a study [1] looks into the societal and ethical impacts of biased algorithms, examining the intricacies of fairness and discrimination in ML models. A paper in [2] highlights significant disparities in model accuracy. Another study [3] interrogates the representational harms in natural language processing models, illustrating how such models can reinforce stereotypical beliefs. In [4], the authors illustrate how AI models can inherit and perpetuate human biases present in the training data, emphasizing the need for careful consideration of data representativeness. A study in [5] offers a comprehensive review of bias and fairness in ML, discussing various bias types, measurement methods, and mitigation strategies. Together, these papers underscore the criticality of acknowledging, understanding, and addressing biases in ML, contributing to the ongoing discourse on ethical AI development.


Addressing and continuously monitoring biases in Machine Learning (ML) is of critical importance to leverage the technology’s full potential ethically and equitably. As ML becomes increasingly integral, a collective, vigilant approach is essential to mitigate biases and ensure fairness in AI systems. Developers and companies must lead this endeavor, prioritizing ethical considerations in AI development to prevent discriminatory and unjust outcomes. However, the pursuit of unbiased and ethical AI is a shared responsibility, necessitating broader audience engagement. Everyone, from developers to end-users, should actively participate in conversations around AI ethics, fostering a more informed, inclusive, and equitable environment.


  1. Pagano, T. P., Loureiro, R. B., Lisboa, F. V., Peixoto, R. M., Guimarães, G. A., Cruz, G. O., … & Nascimento, E. G. (2023). Bias and unfairness in machine learning models: a systematic review on datasets, tools, fairness metrics, and identification and mitigation methods. Big data and cognitive computing7(1), 15.
  2. O’Connor, S., & Liu, H. (2023). Gender bias perpetuation and mitigation in AI technologies: challenges and opportunities. AI & SOCIETY, 1-13.
  3. Mitchell, M., Wu, S., Zaldivar, A., Barnes, P., Vasserman, L., Hutchinson, B., … & Gebru, T. (2019, January). Model cards for model reporting. In Proceedings of the conference on fairness, accountability, and transparency (pp. 220-229).
  4. Caliskan, A., Bryson, J. J., & Narayanan, A. (2017). Semantics derived automatically from language corpora contain human-like biases. Science356(6334), 183-186.
  5. Mehrabi, N., Morstatter, F., Saxena, N., Lerman, K., & Galstyan, A. (2021). A survey on bias and fairness in machine learning. ACM computing surveys (CSUR)54(6), 1-35.

For 30+ years, I've been committed to protecting people, businesses, and the environment from the physical harm caused by cyber-kinetic threats, blending cybersecurity strategies and resilience and safety measures. Lately, my worries have grown due to the rapid, complex advancements in Artificial Intelligence (AI). Having observed AI's progression for two decades and penned a book on its future, I see it as a unique and escalating threat, especially when applied to military systems, disinformation, or integrated into critical infrastructure like 5G networks or smart grids. More about me.

Luka Ivezic
Luka Ivezic

Luka Ivezic is the Lead Cybersecurity Consultant for Europe at the Information Security Forum (ISF), a leading global, independent, and not-for-profit organisation dedicated to cybersecurity and risk management. Before joining ISF, Luka served as a cybersecurity consultant and manager at PwC and Deloitte. His journey in the field began as an independent researcher focused on cyber and geopolitical implications of emerging technologies such as AI, IoT, 5G. He co-authored with Marin the book "The Future of Leadership in the Age of AI". Luka holds a Master's degree from King's College London's Department of War Studies, where he specialized in the disinformation risks posed by AI.

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