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Babak Salimi

dblp:11/6446 · DBLP profile ↗
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34ranked-venue papers
6as first author
22since 2021 · last 2025
0000-0003-2485-9533ORCID · conflict

Domains — the database's venue-derived domains; a paper can count in several

Databases, data management, data science and information retrieval · 25 · 6 first-author · 16 since 2021Artificial intelligence and machine learning · 6 · 5 since 2021Systems, architecture and hardware · 1Security and privacy · 1 · 1 since 2021Theory of computation · 1

Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.

Artificial intelligence
16 papers
Trustworthy machine learning · 85% Probabilistic and Bayesian machine learning · 7% Generative modeling · 4%
Databases, data mining, and information retrieval
22 papers
Data integration and cleaning · 39% Query processing and optimization · 14% Data mining · 14%

Topics — the 30 heaviest of 58, each with the papers that count most for it

TopicWeightPapersLastEvidence papers
Machine learning › Trustworthy machine learning
interpretability
3.362022
Generating Interpretable Data-Based Explanations for Fairness Debugging using Gopher · SIGMOD Conference 2022
Interpretable Data-Based Explanations for Fairness Debugging · SIGMOD Conference 2022
Explainable AI: Foundations, Applications, Opportunities for Data Management Research · SIGMOD Conference 2022
Machine learning › Trustworthy machine learning
fairness
3.062025
Consistent Range Approximation for Fair Predictive Modeling · Proc. VLDB Endow. 2023
Generating Interpretable Data-Based Explanations for Fairness Debugging using Gopher · SIGMOD Conference 2022
Interpretable Data-Based Explanations for Fairness Debugging · SIGMOD Conference 2022
Data integration and cleaning
data quality
1.722025
Stress-Testing ML Pipelines with Adversarial Data Corruption · Proc. VLDB Endow. 2025
Navigating Data Errors in Machine Learning Pipelines: Identify, Debug, and Learn · ICDE 2025
Machine learning › Trustworthy machine learning › interpretability
explainable AI
1.632022
Explainable AI: Foundations, Applications, Opportunities for Data Management Research · SIGMOD Conference 2022
Explainable AI: Foundations, Applications, Opportunities for Data Management Research · ICDE 2022
Demonstration of Generating Explanations for Black-Box Algorithms Using Lewis · Proc. VLDB Endow. 2021
Data mining
causal inference
1.232020
Demonstration of Inferring Causality from Relational Databases with CaRL · Proc. VLDB Endow. 2020
Causal Relational Learning · SIGMOD Conference 2020
ZaliQL: Causal Inference from Observational Data at Scale · Proc. VLDB Endow. 2017
Machine learning › Probabilistic and Bayesian machine learning
causal inference
1.022025
Causal DAG Summarization · Proc. VLDB Endow. 2025
Explaining Black-Box Algorithms Using Probabilistic Contrastive Counterfactuals · SIGMOD Conference 2021
Machine learning › Trustworthy machine learning › interpretability
counterfactual explanation
1.022021
Demonstration of Generating Explanations for Black-Box Algorithms Using Lewis · Proc. VLDB Endow. 2021
Explaining Black-Box Algorithms Using Probabilistic Contrastive Counterfactuals · SIGMOD Conference 2021
Machine learning › Generative modeling › diffusion model
memorization mitigation
0.912025
TokenSwap: A Lightweight Method to Disrupt Memorized Sequences in LLMs · NeurIPS 2025
Machine learning › Trustworthy machine learning
privacy and data protection
0.912025
TokenSwap: A Lightweight Method to Disrupt Memorized Sequences in LLMs · NeurIPS 2025
Machine learning › Trustworthy machine learning
robustness
0.912025
Stress-Testing ML Pipelines with Adversarial Data Corruption · Proc. VLDB Endow. 2025
Machine learning › Trustworthy machine learning › privacy
training data memorization
0.912025
TokenSwap: A Lightweight Method to Disrupt Memorized Sequences in LLMs · NeurIPS 2025
Data integration and cleaning › data preprocessing
data cleaning
0.912025
KAIROS: Scalable Model-Agnostic Data Valuation · NeurIPS 2025
Machine learning and data management
data valuation
0.912025
KAIROS: Scalable Model-Agnostic Data Valuation · NeurIPS 2025
Data integration and cleaning › data quality
error repair
0.912025
Navigating Data Errors in Machine Learning Pipelines: Identify, Debug, and Learn · ICDE 2025
Graph data management
graph summarization
0.912025
Causal DAG Summarization · Proc. VLDB Endow. 2025
Machine learning › Trustworthy machine learning › model multiplicity
predictive multiplicity
0.812024
Learning from Uncertain Data: From Possible Worlds to Possible Models · NeurIPS 2024
Machine learning › Trustworthy machine learning › robustness
robust learning
0.812024
Learning from Uncertain Data: From Possible Worlds to Possible Models · NeurIPS 2024
Machine learning › Trustworthy machine learning › uncertainty estimation
uncertain data
0.812024
Learning from Uncertain Data: From Possible Worlds to Possible Models · NeurIPS 2024
Machine learning › Trustworthy machine learning
uncertainty estimation
0.812024
Learning from Uncertain Data: From Possible Worlds to Possible Models · NeurIPS 2024
Data integration and cleaning › data preprocessing › data cleaning
data repair
0.812024
OTClean: Data Cleaning for Conditional Independence Violations using Optimal Transport · Proc. ACM Manag. Data 2024
Machine learning › Trustworthy machine learning › fairness
fair prediction
0.712023
Consistent Range Approximation for Fair Predictive Modeling · Proc. VLDB Endow. 2023
Data integration and cleaning › table understanding › table annotation
attribute discovery
0.712023
Causal Data Integration · Proc. VLDB Endow. 2023
Data mining › causal inference
causal explanation
0.712023
On Explaining Confounding Bias · ICDE 2023
Data integration and cleaning › data quality › inconsistency handling
inconsistency-tolerant query answering
0.712023
Consistent Range Approximation for Fair Predictive Modeling · Proc. VLDB Endow. 2023
Data integration and cleaning › data quality
inconsistent data
0.712023
Consistent Range Approximation for Fair Predictive Modeling · Proc. VLDB Endow. 2023
Query processing and optimization › OLAP
OLAP query processing
0.722018
HypDB: A Demonstration of Detecting, Explaining and Resolving Bias in OLAP queries · Proc. VLDB Endow. 2018
Bias in OLAP Queries: Detection, Explanation, and Removal · SIGMOD Conference 2018
Query processing and optimization
query rewriting
0.722018
HypDB: A Demonstration of Detecting, Explaining and Resolving Bias in OLAP queries · Proc. VLDB Endow. 2018
Bias in OLAP Queries: Detection, Explanation, and Removal · SIGMOD Conference 2018
Machine learning › Trustworthy machine learning › interpretability
causal explanation
0.612022
Interpretable Data-Based Explanations for Fairness Debugging · SIGMOD Conference 2022
Machine learning › Trustworthy machine learning › fairness
fair classification
0.612022
Through the Data Management Lens: Experimental Analysis and Evaluation of Fair Classification · SIGMOD Conference 2022
Data integration and cleaning
dependency discovery
0.412020
Mining Approximate Acyclic Schemes from Relations · SIGMOD Conference 2020

Methods — techniques the papers use, named apart from their topics

causal inference · 4.3wasserstein distance · 1.7maximum mean discrepancy · 1.7greedy algorithm · 1.7data shapley · 1.7bi-level optimization · 1.7adversarial data corruption · 1.7sinkhorn matrix scaling · 1.5quadratically constrained linear program · 1.5optimal transport · 1.5probabilistic contrastive counterfactual · 1.0token probability swapping · 0.9small model assistance · 0.9model debugging · 0.9data profiling · 0.9corruption templates · 0.9hypothesis testing · 0.6data visualization · 0.6
YearPublicationVenuePosition
2025 Graph Machine Learning based Doubly Robust Estimator for Network Causal Effects
abstract
Estimating causal effects in social network data presents unique challenges due to the presence of spillover effects and network-induced confounding. While much of the existing literature addresses causal inference in social networks, many methods rely on strong assumptions about the form of network-induced confounding. These assumptions often fail to hold in high-dimensional networks, limiting the applicability of such approaches. To address this, we propose a novel methodology that integrates graph machine learning techniques with the double machine learning framework, facilitating accurate and efficient estimation of both direct and peer effects in a single observational social network. Our estimator achieves semiparametric efficiency under mild regularity conditions, enabling consistent uncertainty quantification. Through extensive simulations, we demonstrate the accuracy, robustness, and scalability of our method. Finally, we apply the proposed approach to examine the impact of Self-Help Group participation on financial risk tolerance, highlighting its practical relevance.
Seyedeh Baharan Khatami, Harsh Parikh, Sudeepa Roy 0001, Babak Salimi
AISTATS5
2025 Scalable Out-of-Distribution Robustness in the Presence of Unobserved Confounders
abstract
We consider the task of out-of-distribution (OOD) generalization, where the distribution shift is due to an unobserved confounder ($Z$) affecting both the covariates ($X$) and the labels ($Y$). This confounding introduces heterogeneity in the predictor, i.e., $P(Y \mid X) = E_{P(Z \mid X)}[P(Y \mid X,Z)]$, making traditional covariate and label shift assumptions unsuitable. OOD generalization differs from traditional domain adaptation in that it does not assume access to the covariate distribution ($X^\text{te}$) of the test samples during training. These conditions create a challenging scenario for OOD robustness: (a) $Z^\text{tr}$ is an unobserved confounder during training, (b) $P^\text{te}(Z) \neq P^\text{tr}(Z)$, (c) $X^\text{te}$ is unavailable during training, and (d) the predictive distribution depends on $P^\text{te}(Z)$. While prior work has developed complex predictors requiring multiple additional variables for identifiability of the latent distribution, we explore a set of identifiability assumptions that yield a surprisingly simple predictor using only a single additional variable. Our approach demonstrates superior empirical performance on several benchmark tasks.
Parjanya Prajakta Prashant, Seyedeh Baharan Khatami, Bruno Ribeiro 0001, Babak Salimi
AISTATS4
2025 Navigating Data Errors in Machine Learning Pipelines: Identify, Debug, and Learn
abstract
Addressing data errors such as wrong, missing, noisy, biased, or out-of-distribution values has become a crucial part of the machine learning (ML) development lifecycle. Un-fortunately, traditional approaches have relied either on treating the symptom by refining the model architecture, or on improving data quality by repairing incorrect values regardless of their significance to the downstream model. Both strategies end up tackling the problem in isolation, and disregard the structure of modern ML pipelines, which involve a series of steps for data preprocessing, model training, and prediction processing. Consequently, they miss the opportunity to consider how different data errors propagate through the pipeline and how they impact its ability to perform downstream tasks. In recent years, the research community has made significant strides towards more holistic approaches for identifying the most harmful data errors, performing the most beneficial repairs, and ensuring reliable performance even if some data errors remain present. This tutorial will survey some prominent work published in this space and showcase several tools that have been developed. By combining theoretical foundations with practical demonstrations, attendees will gain actionable strategies to diagnose and mitigate data quality issues, improving the reliability, fairness, and transparency of ML systems in real-world settings.
Bojan Karlas, Babak Salimi, Sebastian Schelter
ICDE2
2025 TokenSwap: A Lightweight Method to Disrupt Memorized Sequences in LLMs
abstract
As language models scale, their performance improves dramatically across a wide range of tasks, but so does their tendency to memorize and regurgitate parts of their training data verbatim. This tradeoff poses serious legal, ethical, and safety concerns, especially in real-world deployments. Existing mitigation techniques, such as differential privacy or model unlearning, often require retraining or access to internal weights making them impractical for most users. In this work, we introduce TokenSwap, a lightweight, post-hoc defense designed for realistic settings where the user can only access token-level outputs. Our key insight is that while large models are necessary for high task performance, small models (e.g., DistilGPT-2) are often sufficient to assign fluent, grammatically plausible probabilities to common function words - and crucially, they memorize far less. By selectively swapping token probabilities between models, TokenSwap preserves the capabilities of large models while reducing their propensity for verbatim reproduction. Evaluations on Pythia-6.9B and Llama-3-8B show up to a 10$\times$ drop in exact memorization with negligible task degradation. Our method offers a practical, accessible solution for mitigating memorized generation in deployed LLMs. Code is available at https://github.com/parjanya20/verbatim-llm.
Parjanya Prajakta Prashant, Kaustubh Ponkshe, Babak Salimi
NeurIPS3
2025 KAIROS: Scalable Model-Agnostic Data Valuation
abstract
Data valuation techniques quantify each training example's contribution to model performance, providing a principled basis for data cleaning, acquisition, and selection. Existing valuation methods remain inadequate: \emph{model-based} techniques depend on a single fitted model and inherit its biases, while \emph{algorithm-based} approaches like Data Shapley scale poorly due to their need to train multiple models. Recent work has proposed model-agnostic alternatives based on Wasserstein distance between the training set and a clean reference set, but exact computation is expensive and approximations often misrank examples. We introduce KAIROS, a model-agnostic framework that values examples by their contribution to the Maximum Mean Discrepancy (MMD) between the training set and a clean reference distribution. Unlike Wasserstein methods, MMD admits a closed-form solution that requires no approximations and is scalable to large datasets. Additionally, KAIROS enables efficient online valuation: adding a new batch of $m$ examples requires only $O(mN)$ computation to update all scores, compared to $O(N^2)$ in prior work where $N$ is the training set size. Empirical evaluations on noise, mislabeling, and poisoning benchmarks show that KAIROS consistently outperforms state-of-the-art baselines in both accuracy and runtime. On ImageNet, KAIROS achieves up to 15 $\times$ speedup over the fastest baseline while maintaining superior data valuation quality. Our results demonstrate that model-agnostic methods can match or exceed model-based approaches in performance while scaling to large datasets.
Jiongli Zhu, Parjanya Prashant, Alexander Cloninger, Babak Salimi
NeurIPS4
2025 Causal DAG Summarization
abstract
Causal inference aids researchers in discovering cause-and-effect relationships, leading to scientific insights. Accurate causal estimation requires identifying confounding variables to avoid false discoveries. Pearl's causal model uses causal DAGs to identify confounding variables, but incorrect DAGs can lead to unreliable causal conclusions. However, for high dimensional data, the causal DAGs are often complex beyond human verifiability. Graph summarization is a logical next step, but current methods for general-purpose graph summarization are inadequate for causal DAG summarization. This paper addresses these challenges by proposing a causal graph summarization objective that balances graph simplification for better understanding while retaining essential causal information for reliable inference. We develop an efficient greedy algorithm and show that summary causal DAGs can be directly used for inference and are more robust to misspecification of assumptions, enhancing robustness for causal inference. Experimenting with six real-life datasets, we compared our algorithm to three existing solutions, showing its effectiveness in handling high-dimensional data and its ability to generate summary DAGs that ensure both reliable causal inference and robustness against misspecifications.
Anna Zeng, Michael J. Cafarella, Batya Kenig, Markos Markakis, Brit Youngmann, Babak Salimi
Proc. VLDB Endow.6
2025 Stress-Testing ML Pipelines with Adversarial Data Corruption
abstract
Structured data-quality issues—such as missing values correlated with demographics, culturally biased labels, or systemic selection biases—routinely degrade the reliability of machine-learning pipelines. Regulators now increasingly demand evidence that high-stakes systems can withstand these realistic, interdependent errors, yet current robustness evaluations typically use random or overly simplistic corruptions, leaving worst-case scenarios unexplored. We introduce Savage, a causally inspired framework that (i) formally models realistic data-quality issues through dependency graphs and flexible corruption templates, and (ii) systematically discovers corruption patterns that maximally degrade a target performance metric. Savage employs a bi-level optimization approach to efficiently identify vulnerable data subpopulations and fine-tune corruption severity, treating the full ML pipeline, including preprocessing and potentially non-differentiable models, as a black box. Extensive experiments across multiple datasets and ML tasks (data cleaning, fairness-aware learning, uncertainty quantification) demonstrate that even a small fraction (around 5%) of structured corruptions identified by Savage severely impacts model performance, far exceeding random or manually crafted errors, and invalidating core assumptions of existing techniques. Thus, Savage provides a practical tool for rigorous pipeline stress-testing, a benchmark for evaluating robustness methods, and actionable guidance for designing more resilient data workflows.
Jiongli Zhu, Geyang Xu, Felipe Lorenzi, Boris Glavic, Babak Salimi
Proc. VLDB Endow.5
2024 Learning from Uncertain Data: From Possible Worlds to Possible Models
abstract
We introduce an efficient method for learning linear models from uncertain data, where uncertainty is represented as a set of possible variations in the data, leading to predictive multiplicity. Our approach leverages abstract interpretation and zonotopes, a type of convex polytope, to compactly represent these dataset variations, enabling the symbolic execution of gradient descent on all possible worlds simultaneously. We develop techniques to ensure that this process converges to a fixed point and derive closed-form solutions for this fixed point. Our method provides sound over-approximations of all possible optimal models and viable prediction ranges. We demonstrate the effectiveness of our approach through theoretical and empirical analysis, highlighting its potential to reason about model and prediction uncertainty due to data quality issues in training data.
Jiongli Zhu, Su Feng, Boris Glavic, Babak Salimi
NeurIPS4
2024 OTClean: Data Cleaning for Conditional Independence Violations using Optimal Transport
abstract
Ensuring Conditional Independence (CI) constraints is pivotal for the development of fair and trustworthy machine learning models. In this paper, we introduce OTClean, a framework that harnesses optimal transport theory for data repair under CI constraints. Optimal transport theory provides a rigorous framework for measuring the discrepancy between probability distributions, thereby ensuring control over data utility. We formulate the data repair problem concerning CIs as a Quadratically Constrained Linear Program (QCLP) and propose an alternating method for its solution. However, this approach faces scalability issues due to the computational cost associated with computing optimal transport distances, such as the Wasserstein distance. To overcome these scalability challenges, we reframe our problem as a regularized optimization problem, enabling us to develop an iterative algorithm inspired by Sinkhorn's matrix scaling algorithm, which efficiently addresses high-dimensional and large-scale data. Through extensive experiments, we demonstrate the efficacy and efficiency of our proposed methods, showcasing their practical utility in real-world data cleaning and preprocessing tasks. Furthermore, we provide comparisons with traditional approaches, highlighting the superiority of our techniques in terms of preserving data utility while ensuring adherence to the desired CI constraints.
Alireza Pirhadi, Mohammad Hossein Moslemi, Alexander Cloninger, Mostafa Milani, Babak Salimi
Proc. ACM Manag. Data5
2023 Causal What-If and How-To Analysis Using HypeR
abstract
What-if and How-to queries are fundamental data analysis questions that provide insights about the effects of a hypothetical update without actually making changes to the database. Traditional systems assume independence across differ¬ent tuples and non-updated attributes of the database. However, different attributes and tuples are generally dependent in real-world scenarios. We propose to demonstrate HypeR, a novel system to efficiently answer what-if and how-to queries while capturing causal dependencies among different attributes and tuples in the database. To compute the results, HypeR leverages a suite of optimizations along with techniques from causal inference to effectively estimate the answers. HypeR allows users to formulate complex hypothetical queries by using a novel SQL-like syntax and presents the output as interactive visualizations that can be explored and analyzed with ease.
Fangzhu Shen, Kayvon Heravi, Oscar Gomez, Sainyam Galhotra, Amir Gilad, Sudeepa Roy 0001, Babak Salimi
ICDE7
2023 On Explaining Confounding Bias
abstract
When analyzing large datasets, analysts are often interested in the explanations for unexpected results produced by their queries. In this work, we focus on aggregate SQL queries that expose correlations in the data. A major challenge that hinders the interpretation of such queries is confounding bias, which can lead to an unexpected correlation. We generate explanations in terms of a set of potential confounding variables that explain the unexpected correlation observed in a query. We propose to mine candidate confounding variables from external sources since, in many real-life scenarios, the explanations are not solely contained in the input data. We present an efficient algorithm that finds a concise subset of attributes (mined from external sources and the input dataset) that explain the unexpected correlation. This algorithm is embodied in a system called MESA. We demonstrate experimentally over multiple real-life datasets and through a user study that our approach generates insightful explanations, outperforming existing methods even when are given with the extracted attributes. We further demonstrate the robustness of our system to missing data and the ability of MESA to handle input datasets containing millions of tuples and an extensive search space of candidate confounding attributes.
Brit Youngmann, Michael J. Cafarella, Yuval Moskovitch, Babak Salimi
ICDE4
2023 SAFE-PASS: Stewardship, Advocacy, Fairness and Empowerment in Privacy, Accountability, Security, and Safety for Vulnerable Groups
abstract
Our vision is to achieve societally responsible secure and trustworthy cyberspace that puts algorithmic and technological checks and balances on the indiscriminate sharing and analysis of data. We achieve this vision in a holistic manner by framing research directions with four major considerations: (i) Expanding knowledge and understanding of security and privacy perceptions and expectations in vulnerable groups, which significantly contribute to their unwillingness to share data, and use that knowledge to drive research in (a) mitigating missing/imbalanced data problems, (b) understanding and modeling security and privacy risks of data sharing, and (c) modeling utility of data sharing. (ii) Developing a risk-adaptive, policy model capable of capturing and articulating security and privacy expectations of users that are relevant in a particular context and develops associated technology to ensure provenance and accountability. (iii) Developing robust AI/ML algorithms that are transparent and explainable with respect to fairness and bias to reduce/eliminate discrimination, misuse, privacy violations, or other cyber-crimes. (iv) Developing models and techniques for a nuanced, contextually adaptive, and graded privacy paradigm that allows trade-offs between privacy and utility. Towards this, in this paper we present the SAFE-PASS framework to provide Stewardship, Advocacy, Fairness and Empowerment in Privacy, Accountability, Security, and Safety for Vulnerable Groups.
Indrajit Ray, Bhavani Thuraisingham, Jaideep Vaidya, Sharad Mehrotra, Vijayalakshmi Atluri, Indrakshi Ray, Murat Kantarcioglu, Ramesh Raskar, Babak Salimi, Steven J. Simske, Nalini Venkatasubramanian, Vivek K. Singh 0001
SACMAT9
2023 Causal Data Integration
abstract
Causal inference is fundamental to empirical scientific discoveries in natural and social sciences; however, in the process of conducting causal inference, data management problems can lead to false discoveries. Two such problems are (i) not having all attributes required for analysis, and (ii) misidentifying which attributes are to be included in the analysis. Analysts often only have access to partial data, and they critically rely on (often unavailable or incomplete) domain knowledge to identify attributes to include for analysis, which is often given in the form of a causal DAG. We argue that data management techniques can surmount both of these challenges. In this work, we introduce the Causal Data Integration (CDI) problem, in which unobserved attributes are mined from external sources and a corresponding causal DAG is automatically built. We identify key challenges and research opportunities in designing a CDI system, and present a system architecture for solving the CDI problem. Our preliminary experimental results demonstrate that solving CDI is achievable and pave the way for future research.
Brit Youngmann, Michael J. Cafarella, Babak Salimi, Anna Zeng
Proc. VLDB Endow.3
2023 Consistent Range Approximation for Fair Predictive Modeling
abstract
This paper proposes a novel framework for certifying the fairness of predictive models trained on biased data. It draws from query answering for incomplete and inconsistent databases to formulate the problem of consistent range approximation (CRA) of fairness queries for a predictive model on a target population. The framework employs background knowledge of the data collection process and biased data, working with or without limited statistics about the target population, to compute a range of answers for fairness queries. Using CRA, the framework builds predictive models that are certifiably fair on the target population, regardless of the availability of external data during training. The framework's efficacy is demonstrated through evaluations on real data, showing substantial improvement over existing state-of-the-art methods.
Jiongli Zhu, Sainyam Galhotra, Nazanin Sabri, Babak Salimi
Proc. VLDB Endow.4
2022 Explainable AI: Foundations, Applications, Opportunities for Data Management Research
abstract
Algorithmic decision-making systems are success-fully being adopted in a wide range of domains for diverse tasks. While the potential benefits of algorithmic decision-making are many, the importance of trusting these systems has only recently attracted attention. There has been a recent resurgence of interest in explainable artificial intelligence (XAI) that aims to reduce the opacity of a model by explaining its behavior, its predictions or both, thus allowing humans to scrutinize and trust the model. A host of technical advances have been made and several explanation methods have been proposed in recent years that address the problem of model explainability. In this tutorial, we will present these novel explanation approaches, characterize their strengths and limitations, and enumerate opportunities for data management research in the context of XAI.
Romila Pradhan, Aditya Lahiri, Sainyam Galhotra, Babak Salimi
ICDE4
2022 HypeR: Hypothetical Reasoning With What-If and How-To Queries Using a Probabilistic Causal Approach
abstract
What-if (provisioning for an update to a database) and how-to (how to modify the database to achieve a goal) analyses provide insights to users who wish to examine hypothetical scenarios without making actual changes to a database and thereby help plan strategies in their fields. Typically, such analyses are done by testing the effect of an update in the existing database on a specific view created by a query of interest. In real-world scenarios, however, an update to a particular part of the database may affect tuples and attributes in a completely different part due to implicit semantic dependencies. To allow for hypothetical reasoning while accommodating such dependencies, we develop HypeR, a framework that supports what-if and how-to queries accounting for probabilistic dependencies among attributes captured by a probabilistic causal model. We extend the SQL syntax to include the necessary operators for expressing these hypothetical queries, define their semantics, devise efficient algorithms and optimizations to compute their results using concepts from causality and probabilistic databases, and evaluate the effectiveness of our approach experimentally.
Sainyam Galhotra, Amir Gilad, Sudeepa Roy 0001, Babak Salimi
SIGMOD Conference4
2022 Through the Data Management Lens: Experimental Analysis and Evaluation of Fair Classification
abstract
Classification, a heavily-studied data-driven machine learning task, drives an increasing number of prediction systems involving critical human decisions such as loan approval and criminal risk assessment. However, classifiers often demonstrate discriminatory behavior, especially when presented with biased data. Consequently, fairness in classification has emerged as a high-priority research area. Data management research is showing an increasing presence and interest in topics related to data and algorithmic fairness, including the topic of fair classification. The interdisciplinary efforts in fair classification, with machine learning research having the largest presence, have resulted in a large number of fairness notions and a wide range of approaches that have not been systematically evaluated and compared. In this paper, we contribute a broad analysis of 13 fair classification approaches and additional variants, over their correctness, fairness, efficiency, scalability, robustness to data errors, sensitivity to underlying ML model, data efficiency, and stability using a variety of metrics and real-world datasets. Our analysis highlights novel insights on the impact of different metrics and high-level approach characteristics on different aspects of performance. We also discuss general principles for choosing approaches suitable for different practical settings, and identify areas where data-management-centric solutions are likely to have the most impact.
Maliha Tashfia Islam, Anna Fariha, Alexandra Meliou, Babak Salimi
SIGMOD Conference4
2022 Explainable AI: Foundations, Applications, Opportunities for Data Management Research
abstract
Algorithmic decision-making systems are successfully being adopted in a wide range of domains for diverse tasks. While the potential benefits of algorithmic decision-making are many, the importance of trusting these systems has only recently attracted attention. There is growing concern that these systems are complex, opaque and non-intuitive, and hence are difficult to trust. There has been a recent resurgence of interest in explainable artificial intelligence (XAI) that aims to reduce the opacity of a model by explaining its behavior, its predictions or both, thus allowing humans to scrutinize and trust the model. A host of technical advances have been made and several explanation methods have been proposed in recent years that address the problem of model explainability and transparency. In this tutorial, we will present these novel explanation approaches, characterize their strengths and limitations, position existing work with respect to the database (DB) community, and enumerate opportunities for data management research in the context of XAI.
Romila Pradhan, Aditya Lahiri, Sainyam Galhotra, Babak Salimi
SIGMOD Conference4
2022 Interpretable Data-Based Explanations for Fairness Debugging
abstract
A wide variety of fairness metrics and eXplainable Artificial Intelligence (XAI) approaches have been proposed in the literature to identify bias in machine learning models that are used in critical real-life contexts. However, merely reporting on a model's bias or generating explanations using existing XAI techniques is insufficient to locate and eventually mitigate sources of bias. We introduce Gopher, a system that produces compact, interpretable, and causal explanations for bias or unexpected model behavior by identifying coherent subsets of the training data that are root-causes for this behavior. Specifically, we introduce the concept of causal responsibility that quantifies the extent to which intervening on training data by removing or updating subsets of it can resolve the bias. Building on this concept, we develop an efficient approach for generating the top-k patterns that explain model bias by utilizing techniques from the machine learning (ML) community to approximate causal responsibility, and using pruning rules to manage the large search space for patterns. Our experimental evaluation demonstrates the effectiveness of Gopher in generating interpretable explanations for identifying and debugging sources of bias.
Romila Pradhan, Jiongli Zhu, Boris Glavic, Babak Salimi
SIGMOD Conference4
2022 Generating Interpretable Data-Based Explanations for Fairness Debugging using Gopher
abstract
Machine learning (ML) models, while increasingly being used to make life-altering decisions, are known to reinforce systemic bias and discrimination. Consequently, practitioners and model developers need tools to facilitate debugging for bias in ML models. We introduce Gopher, a system that generates compact, interpretable and causal explanations for ML model bias. Gopher identifies the top-k coherent subsets of the training data that are root causes for model bias by quantifying the extent to which removing or updating a subset can resolve the bias. We describe the architecture of Gopher and will walk the audience through real-world use cases to highlight how Gopher generates explanations that enable data scientists to understand how subsets of the training data contribute to the bias of a machine learning (ML) model. Gopher is available as open-source software; The code and the demonstration video are available at https://gopher-sys.github.io/.
Jiongli Zhu, Romila Pradhan, Boris Glavic, Babak Salimi
SIGMOD Conference4
2021 Explaining Black-Box Algorithms Using Probabilistic Contrastive Counterfactuals
abstract
There has been a recent resurgence of interest in explainable artificial intelligence (XAI) that aims to reduce the opaqueness of AI-based decision-making systems, allowing humans to scrutinize and trust them. Prior work in this context has focused on the attribution of responsibility for an algorithm's decisions to its inputs wherein responsibility is typically approached as a purely associational concept. In this paper, we propose a principled causality-based approach for explaining black-box decision-making systems that addresses limitations of existing methods in XAI. At the core of our framework lies probabilistic contrastive counterfactuals, a concept that can be traced back to philosophical, cognitive, and social foundations of theories on how humans generate and select explanations. We show how such counterfactuals can quantify the direct and indirect influences of a variable on decisions made by an algorithm, and provide actionable recourse for individuals negatively affected by the algorithm's decision. Unlike prior work, our system, LEWIS: (1)~can compute provably effective explanations and recourse at local, global and contextual levels; (2)~is designed to work with users with varying levels of background knowledge of the underlying causal model; and (3)~makes no assumptions about the internals of an algorithmic system except for the availability of its input-output data. We empirically evaluate LEWIS on four real-world datasets and show that it generates human-understandable explanations that improve upon state-of-the-art approaches in XAI, including the popular LIME and SHAP. Experiments on synthetic data further demonstrate the correctness of LEWIS's explanations and the scalability of its recourse algorithm.
Sainyam Galhotra, Romila Pradhan, Babak Salimi
SIGMOD Conference3
2021 Demonstration of Generating Explanations for Black-Box Algorithms Using Lewis
abstract
Explainable artificial intelligence (XAI) aims to reduce the opacity of AI-based decision-making systems, allowing humans to scrutinize and trust them. Unlike prior work that attributes the responsibility for an algorithm's decisions to its inputs as a purely associational concept, we propose a principled causality-based approach for explaining black-box decision-making systems. We present the demonstration of Lewis, a system that generates explanations for black-box algorithms at the global, contextual, and local levels, and provides actionable recourse for individuals negatively affected by an algorithm's decision. Lewis makes no assumptions about the internals of the algorithm except for the availability of its input-output data. The explanations generated by Lewis are based on probabilistic contrastive counterfactuals, a concept that can be traced back to philosophical, cognitive, and social foundations of theories on how humans generate and select explanations. We describe the system layout of Lewis wherein an end-user specifies the underlying causal model and Lewis generates explanations for particular use-cases, compares them with explanations generated by state-of-the-art approaches in XAI, and provides actionable recourse when applicable. Lewis has been developed as open-source software; the code and the demonstration video are available at lewis-system.github.io.
Paul Y. Wang, Sainyam Galhotra, Romila Pradhan, Babak Salimi
Proc. VLDB Endow.4
2020 Mining Approximate Acyclic Schemes from Relations
abstract
Acyclic schemes have numerous applications in databases and in machine learning, such as improved design, more efficient storage, and increased performance for queries and machine learning algorithms. Multivalued dependencies (MVDs) are the building blocks of acyclic schemes. The discovery from data of both MVDs and acyclic schemes is more challenging than other forms of data dependencies, such as Functional Dependencies, because these dependencies do not hold on subsets of data, and because they are very sensitive to noise in the data; for example a single wrong or missing tuple may invalidate the schema. In this paper we present Maimon, a system for discovering approximate acyclic schemes and MVDs from data. We give a principled definition of approximation, by using notions from information theory, then describe the two components of Maimon: mining for approximate MVDs, then reconstructing acyclic schemes from approximate MVDs. We conduct an experimental evaluation of Maimon on 20 real-world datasets, and show that it can scale up to 1M rows, and up to 30 columns.
Batya Kenig, Pranay Mundra, Guna Prasaad, Babak Salimi, Dan Suciu
SIGMOD Conference4
2020 Causal Relational Learning
abstract
Causal inference is at the heart of empirical research in natural and social sciences and is critical for scientific discovery and informed decision making. The gold standard in causal inference is performing randomized controlled trials ; unfortunately these are not always feasible due to ethical, legal, or cost constraints. As an alternative, methodologies for causal inference from observational data have been developed in statistical studies and social sciences. However, existing methods critically rely on restrictive assumptions such as the study population consisting of homogeneous elements that can be represented in a single flat table, where each row is referred to as a unit. In contrast, in many real-world settings, the study domain naturally consists of heterogeneous elements with complex relational structure, where the data is naturally represented in multiple related tables. In this paper, we present a formal framework for causal inference from such relational data. We propose a declarative language called CARL for capturing causal background knowledge and assumptions, and specifying causal queries using simple Datalog-like rules. CARL provides a foundation for inferring causality and reasoning about the effect of complex interventions in relational domains. We present an extensive experimental evaluation on real relational data to illustrate the applicability of CARL in social sciences and healthcare.
Babak Salimi, Harsh Parikh, Moe Kayali, Lise Getoor, Sudeepa Roy 0001, Dan Suciu
SIGMOD Conference1
2020 Demonstration of Inferring Causality from Relational Databases with CaRL
abstract
Understanding cause-and-effect is key for informed decision-making. The gold standard in causal inference is performing controlled experiments, which may not always be feasible due to ethical, legal, or cost constraints. As an alternative, inferring causality from observational data has been extensively used in statistics and social sciences. However, the existing methods critically rely on a restrictive assumption that the population of study consists of homogeneous units that can be represented as a single flat table. In contrast, in many real-world settings, the study domain consists of heterogeneous units that are best represented using relational databases. We propose and demonstrate CaRL: an end-to-end system for drawing causal inference from relational data. In addition, we built a visual interface to wrap around CaRL. In our demonstration, we will use this GUI to show a live investigation of causal inference from real academic and medical relational databases.
Moe Kayali, Babak Salimi, Dan Suciu
Proc. VLDB Endow.2
2019 Interventional Fairness: Causal Database Repair for Algorithmic Fairness
abstract
Fairness is increasingly recognized as a critical component of machine learning systems. However, it is the underlying data on which these systems are trained that often reflect discrimination, suggesting a database repair problem. Existing treatments of fairness rely on statistical correlations that can be fooled by statistical anomalies, such as Simpson's paradox. Proposals for causality-based definitions of fairness can correctly model some of these situations, but they require specification of the underlying causal models. In this paper, we formalize the situation as a database repair problem, proving sufficient conditions for fair classifiers in terms of admissible variables as opposed to a complete causal model. We show that these conditions correctly capture subtle fairness violations. We then use these conditions as the basis for database repair algorithms that provide provable fairness guarantees about classifiers trained on their training labels. We evaluate our algorithms on real data, demonstrating improvement over the state of the art on multiple fairness metrics proposed in the literature while retaining high utility.
Babak Salimi, Luke Rodriguez, Bill Howe, Dan Suciu
SIGMOD Conference1
2018 Bias in OLAP Queries: Detection, Explanation, and Removal
abstract
On line analytical processing (OLAP) is an essential element of decision-support systems. OLAP tools provide insights and understanding needed for improved decision making. However, the answers to OLAP queries can be biased and lead to perplexing and incorrect insights. In this paper, we propose, a system to detect, explain, and to resolve bias in decision-support queries. We give a simple definition of a biased query, which performs a set of independence tests on the data to detect bias. We propose a novel technique that gives explanations for bias, thus assisting an analyst in understanding what goes on. Additionally, we develop an automated method for rewriting a biased query into an unbiased query, which shows what the analyst intended to examine. In a thorough evaluation on several real datasets we show both the quality and the performance of our techniques, including the completely automatic discovery of the revolutionary insights from a famous 1973 discrimination case.
Babak Salimi, Johannes Gehrke, Dan Suciu
SIGMOD Conference1
2018 HypDB: A Demonstration of Detecting, Explaining and Resolving Bias in OLAP queries
abstract
On line analytical processing (OLAP) is an essential element of decision-support systems. However, OLAP queries can be biased and lead to perplexing and incorrect insights. In this demo, we present HypDB, the first system to detect, explain and resolve bias in OLAP queries. Our demonstration, shows several examples of OLAP queries from real world datasets that are biased and could lead to statistical anomalies such as Simpson's paradox. Then, we demonstrate step-by-step how HypDB: (1) detects whether an OLAP query is biased, (2) explains the root causes of the bias and reveals illuminating insights about the domain and the data collection process and (3) eliminates the bias via query rewriting and generates decision-support insights.
Babak Salimi, Corey Cole, Peter Li, Johannes Gehrke, Dan Suciu
Proc. VLDB Endow.1
2017 A Demonstration of Interactive Analysis of Performance Measurements with Viska
abstract
The ultimate goal of system performance analysis is to identify the underlying causes for performance differences between different systems and different workloads. We make this goal easier to achieve with Viska, a new tool for generating and interpreting performance measurement results. Viska leverages cutting-edge techniques from big data analytics and data visualization to aid and automate this analysis, and helps users derive meaningful and statistically sound conclusions using state-of-the-art causal inference and hypothesis testing techniques.
Helga Gudmundsdottir, Babak Salimi, Magdalena Balazinska, Dan R. K. Ports, Dan Suciu
SIGMOD Conference2
2017 Causes for query answers from databases: Datalog abduction, view-updates, and integrity constraints
Leo Bertossi, Babak Salimi
Int. J. Approx. Reason.2
2017 From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back
Leo Bertossi, Babak Salimi
Theory Comput. Syst.2
2017 ZaliQL: Causal Inference from Observational Data at Scale
abstract
Causal inference from observational data is a subject of active research and development in statistics and computer science. Many statistical software packages have been developed for this purpose. However, these toolkits do not scale to large datasets. We propose and demonstrate ZaliQL: a SQL-based framework for drawing causal inference from observational data. ZaliQL supports the state-of-the-art methods for causal inference and runs at scale within PostgreSQL database system. In addition, we built a visual interface to wrap around ZaliQL. In our demonstration, we will use this GUI to show a live investigation of the causal effect of different weather conditions on flight delays.
Babak Salimi, Corey Cole, Dan R. K. Ports, Dan Suciu
Proc. VLDB Endow.1
2015 From Causes for Database Queries to Repairs and Model-Based Diagnosis and Back
abstract
In this work we establish and investigate connections between causality for query answers in databases, database repairs wrt. denial constraints, and consistency-based diagnosis. The first two are relatively new problems in databases, and the third one is an established subject in knowledge representation. We show how to obtain database repairs from causes and the other way around. Causality problems are formulated as diagnosis problems, and the diagnoses provide causes and their responsibilities. The vast body of research on database repairs can be applied to the newer problem of determining actual causes for query answers and their responsibilities. These connections, which are interesting per se, allow us, after a transition-inspired by consistency-based diagnosis- to computational problems on hitting sets and vertex covers in hypergraphs, to obtain several new algorithmic and complexity results for database causality.
Babak Salimi, Leo Bertossi
ICDT1
1990 On the Diagnostic Resolution of Signature Analysis
abstract
An examination was made of the diagnostic properties of signature analysis. By theoretical and experimental studies the authors derived the probabilities that a given number of signatures occur during a test, and that a given number of signatures will be produced uniquely (i.e. by one fault). These characteristics were validated by a series of simulations of the benchmark circuits under test together with a response compaction procedure using linear feedback shift registers (LFSRs) implementing primitive polynomials. The experimental results confirm the validity of the theoretical model. The authors perform further calculations in order to reveal some important relationships between the size of the used LFSR, the total number of faults and the diagnostic resolution of signature analysis. Indeed, these results provide justification for the adoption of a simple formula that encompasses all the factors considered in the signature analysis compaction technique. Because of its simplicity it can be used directly in VLSI BIST design as well as in a wide range of other applications.>
Janusz Rajski, Jerzy Tyszer, Babak Salimi
ICCAD3