Jason Lefever

Researcher / Software Engineer

About Me

Headshot

I am a computer science researcher and software engineer with roughly ten years of experience across both. My broader interests include machine learning, software architecture, and formal methods. I currently work as a quantitative developer building trading strategies and tools at SIG.

I completed my PhD at Drexel University, where I was advised by Dr. Yuanfang Cai and co-advised by Dr. Rick Kazman. My research focused on software representation and repair using fine-tuned embeddings that help identify where the design of a system is breaking down.

During my PhD, I did research internships at AWS with Dr. Martin Schäf and at NEC Labs with Dr. Tingfeng Li. Earlier, I was a software engineer at WebstaurantStore under Bill Blaettler, and did undergraduate research at YCP with Dr. David Hovemeyer.

Publications

2026

  • J. Lefever, Y. Cai, R. Kazman, and E. Pisch. ConcernBERT: Learning Responsibilities Using Class Membership. IEEE Transactions on Software Engineering (TSE). 2026. [PDF]
    [Bibtex]
    @article{Lefever2026ConcernBERT,
  author       = {Lefever, Jason and Cai, Yuanfang and Kazman, Rick and Pisch, Ernst},
  title        = {ConcernBERT: Learning Responsibilities Using Class Membership},
  journal      = {IEEE Transactions on Software Engineering},
  year         = {2026},
  publisher    = {IEEE},
  url          = {https://ieeexplore.ieee.org/abstract/document/11581324},
  eprint       = {2606.21647},
  archiveprefix = {arXiv},
  primaryclass = {cs.SE}
}
  • J. Lefever, M. N. Mansur, J. Konstantinides, M. Schäf, and W. Visser. Why is This on My Bill? Documentation-Grounded Rule Learning for Itemized Bill Explanation. 41st IEEE/ACM International Conference on Automated Software Engineering, Industry Showcase Track (ASE '26). 2026. [PDF]
    [Bibtex]
    @misc{Lefever2026Bill,
  author       = {Lefever, Jason and Mansur, Muhammad Numair and Konstantinides, John and Sch{\"a}f, Martin and Visser, Willem},
  title        = {Why is This on My Bill? Documentation-Grounded Rule Learning for Itemized Bill Explanation},
  year         = {2026},
  howpublished = {41st IEEE/ACM International Conference on Automated Software Engineering (ASE '26), Industry Showcase Track},
  url          = {https://www.amazon.science/publications/why-is-this-on-my-bill-documentation-grounded-rule-learning-for-itemized-bill-explanation}
}

2025

  • J. Lefever, Y. Cai, R. Kazman, and E. Pisch. Deicide: Decomposing Complex Files Into Responsibility Modules. 2025 IEEE 22nd International Conference on Software Architecture (ICSA). ICSA '25. 2025. 
    [Bibtex]
    @inproceedings{Lefever2025Deicide,
  author    = {Lefever, Jason and Cai, Yuanfang and Kazman, Rick and Pisch, Ernst},
  title     = {Deicide: Decomposing Complex Files Into Responsibility Modules},
  booktitle = {2025 IEEE 22nd International Conference on Software Architecture (ICSA)},
  year      = {2025},
  publisher = {IEEE},
  url       = {https://ieeexplore.ieee.org/abstract/document/10978935}
}
  • J. Lefever. Concern-Based Management of Software Design Complexity. 2025 IEEE/ACM 47th International Conference on Software Engineering: Companion Proceedings (ICSE-Companion). ICSE '25. 2025. 
    [Bibtex]
    @inproceedings{Lefever2025Concern,
  author    = {Lefever, Jason},
  title     = {Concern-Based Management of Software Design Complexity},
  booktitle = {2025 IEEE/ACM 47th International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)},
  year      = {2025},
  publisher = {IEEE},
  doi       = {10.1109/ICSE-Companion66252.2025.00033}
}
  • H. Fang, Y. Cai, E. Tempero, R. Kazman, Y.-C. Tu, J. Lefever, and E. Pisch. A Holistic Approach to Design Understanding Through Concept Explanation. IEEE Transactions on Software Engineering (TSE). 2025. 
    [Bibtex]
    @article{Fang2025Holistic,
  author    = {Fang, Hongzhou and Cai, Yuanfang and Tempero, Ewan and Kazman, Rick and Tu, Yu-Cheng and Lefever, Jason and Pisch, Ernst},
  title     = {A Holistic Approach to Design Understanding Through Concept Explanation},
  journal   = {IEEE Transactions on Software Engineering},
  year      = {2025},
  publisher = {IEEE},
  doi       = {10.1109/TSE.2024.3522973}
}

2024

  • E. Pisch, Y. Cai, R. Kazman, J. Lefever, and H. Fang. M-score: An Empirically Derived Software Modularity Metric. Proceedings of the 18th ACM/IEEE International Symposium on Empirical Software Engineering and Measurement. ESEM '24. 2024. 
    [Bibtex]
    @inproceedings{Pisch2024Mscore,
  author    = {Pisch, Ernst and Cai, Yuanfang and Kazman, Rick and Lefever, Jason and Fang, Hongzhou},
  title     = {M-score: An Empirically Derived Software Modularity Metric},
  booktitle = {Proceedings of the 18th ACM/IEEE International Symposium on Empirical Software Engineering and Measurement (ESEM '24)},
  year      = {2024},
  publisher = {ACM},
  doi       = {10.1145/3674805.3686697}
}
  • A. Liu, J. Lefever, Y. Han, and Y. Cai. Prevalence and Severity of Design Anti-Patterns in Open Source Programs — A Large-Scale Study. Information and Software Technology 170. 2024. 
    [Bibtex]
    @article{Liu2024Prevalence,
  author    = {Liu, Alan and Lefever, Jason and Han, Yi and Cai, Yuanfang},
  title     = {Prevalence and Severity of Design Anti-Patterns in Open Source Programs --- A Large-Scale Study},
  journal   = {Information and Software Technology},
  volume    = {170},
  year      = {2024},
  publisher = {Elsevier},
  doi       = {10.1016/j.infsof.2024.107429}
}

2023

  • J. Lefever, Y. Cai, R. Kazman, and H. Fang. Towards the Assisted Decomposition of Large-Active Files. 2023 IEEE 20th International Conference on Software Architecture Companion (ICSA-C). ICSA '23. 2023. [PDF]
    [Bibtex]
    @inproceedings{Lefever2023Towards,
  author       = {Lefever, Jason and Cai, Yuanfang and Kazman, Rick and Fang, Hongzhou},
  title        = {Towards the Assisted Decomposition of Large-Active Files},
  booktitle    = {2023 IEEE 20th International Conference on Software Architecture Companion (ICSA-C)},
  year         = {2023},
  publisher    = {IEEE},
  url          = {https://www.computer.org/csdl/proceedings-article/icsa-c/2023/645900a126/1MBDfvCze8M},
  eprint       = {2302.09153},
  archiveprefix = {arXiv},
  primaryclass = {cs.SE}
}
  • H. Fang, Y. Cai, R. Kazman, and J. Lefever. Identifying Anti-Patterns in Distributed Systems With Heterogeneous Dependencies. 2023 IEEE 20th International Conference on Software Architecture Companion (ICSA-C). ICSA '23. 2023. 
    [Bibtex]
    @inproceedings{Fang2023Identifying,
  author    = {Fang, Hongzhou and Cai, Yuanfang and Kazman, Rick and Lefever, Jason},
  title     = {Identifying Anti-Patterns in Distributed Systems With Heterogeneous Dependencies},
  booktitle = {2023 IEEE 20th International Conference on Software Architecture Companion (ICSA-C)},
  year      = {2023},
  publisher = {IEEE},
  url       = {https://ieeexplore.ieee.org/document/10092708}
}

2022

  • H. Fang, Y. Cai, R. Kazman, and J. Lefever. CIDER: Concept-based Interactive Design Recovery. Proceedings of the ACM/IEEE 44th International Conference on Software Engineering: Companion Proceedings (ICSE-Companion). ICSE '22. 2022. [PDF]
    [Bibtex]
    @inproceedings{Fang2022CIDER,
  author    = {Fang, Hongzhou and Cai, Yuanfang and Kazman, Rick and Lefever, Jason},
  title     = {CIDER: Concept-based Interactive Design Recovery},
  booktitle = {Proceedings of the ACM/IEEE 44th International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)},
  year      = {2022},
  publisher = {ACM},
  doi       = {10.1145/3510454.3516861},
  url       = {https://par.nsf.gov/servlets/purl/10359522}
}

2021

  • J. Lefever, Y. Cai, H. Cervantes, R. Kazman, and H. Fang. On the Lack of Consensus Among Technical Debt Detection Tools. 2021 IEEE/ACM 43rd International Conference on Software Engineering: Software Engineering in Practice (ICSE-SEIP). ICSE '21. 2021. 
    [Bibtex]
    @inproceedings{Lefever2021Lack,
  author       = {Lefever, Jason and Cai, Yuanfang and Cervantes, Humberto and Kazman, Rick and Fang, Hongzhou},
  title        = {On the Lack of Consensus Among Technical Debt Detection Tools},
  booktitle    = {2021 IEEE/ACM 43rd International Conference on Software Engineering: Software Engineering in Practice (ICSE-SEIP)},
  year         = {2021},
  publisher    = {IEEE},
  url          = {https://arxiv.org/abs/2103.04506},
  eprint       = {2103.04506},
  archiveprefix = {arXiv},
  primaryclass = {cs.SE}
}

2019

  • T. W. Price, D. Hovemeyer, K. Rivers, A. C. Bart, A. Petersen, B. A. Becker, and J. Lefever. Progsnap 2: A Flexible Format for Programming Process Data. Proceedings of the Educational Data Mining in Computer Science Workshop in the Companion Proceedings of the International Conference on Learning Analytics and Knowledge. EDM '19. 2019. 
    [Bibtex]
    @inproceedings{Price2019Progsnap2,
  author    = {Price, Thomas W. and Hovemeyer, David and Rivers, Kelly and Bart, Austin C. and Petersen, Andrew and Becker, Brett A. and Lefever, Jason},
  title     = {ProgSnap2: A Flexible Format for Programming Process Data},
  booktitle = {Companion Proceedings of the International Conference on Learning Analytics and Knowledge (Educational Data Mining in Computer Science Workshop)},
  year      = {2019},
  url       = {https://isnap.csc.ncsu.edu/home/public/publication/price-2019-csedm-ps/}
}