I’m a medical informaticist, software engineer, and data architect, working on real-world evidence studies — administrative claims, EHR, and registry data — with the epidemiologists and clinical researchers who design them. I’m currently Senior Research Informatics Applications Architect at Johns Hopkins School of Medicine (Biomedical Informatics and Data Science, BIDS), where I work across observational study design, cohort building and phenotyping, clinical terminologies, and interactive visualization, on the National COVID Cohort Collaborative (N3C), BioData Catalyst, and Bridge2AI.

I’ve spent years building data infrastructure and analytic tooling alongside the epidemiologists and clinical researchers who design observational studies. I have particular expertise around misclassification bias: whether a cohort definition actually captures the patients it claims to, and whether available data covers the clinical histories a study depends on. Validating that properly requires a reference standard based on medical record abstraction, which is frequently skipped — so the problem routinely goes unexamined until it has already shaped a result. I build tools that surface it early: patient-timeline and event-sequence visualizations, and interfaces for navigating sprawling, overlapping vocabularies behind cohort definitions. VS-Hub, the platform I led, is used by 200+ researchers to author, compare, and validate the concept sets defining cohorts in N3C.

I completed a PhD at the University of Maryland iSchool (2024), with a dissertation on value sets for real-world patient data analysis, and I hold an MA in Biomedical Informatics from Columbia University and an MFA in Creative Writing from Sarah Lawrence College. Earlier work includes building the Patient Profile visualization in OHDSI’s ATLAS and collaborative research with the UMD Human-Computer Interaction Lab on temporal event visualization (EventFlow). I also work on preparing complex biomedical data for AI applications, and I use LLMs heavily in my own engineering and analysis.

Featured Projects

  • VS-Hub (TermHub). Exploration and comparison for National COVID Cohort Collaborative concept sets (2022 - 2024) — Live demo — Source code — National COVID Cohort Collaborative
  • MERKI Medication Parser. Medication extraction from clinical text — AMIA 2008 Distinguished Paper Award — PubMed Central — Live demo — Source code
  • BDCHM Interactive Model Documentation. Dynamic, navigable documentation of the Biomedical Data Commons and Harmonization Model — Documentation
  • ICD-11 Foundation Visualization. Interactive visualization of the ICD-11 Foundation component — Live demo

Publications

Citation metrics on Google Scholar.

  • AI-Enabled Public Health Surveillance: Interim Findings from a Scoping Review of Governance and Implementation Frameworks. Erika Ito, Leroy Harris, Sigfried Gold, Adler Archer. Studies in Health Technology and Informatics 338: 211-212, 2026 — DOI
  • Value sets and the problem of redundancy in value set repositories. Gold S, Lehmann HP, Schilling LM, Lutters WG. PLoS ONE 19(12): e0312289, 2024 — DOI
  • Value Set Hub: Software for developing and curating high-quality value sets. Sigfried Gold, Joseph E. Flack IV, Wayne G. Lutters, Christopher G. Chute. medRxiv, 2024 — medRxiv
  • Value Sets for the Analysis of Real-World Patient Data: Problems, Theory, and Solutions. Sigfried Gold. University of Maryland, College Park — ProQuest Dissertations & Theses, 2024 — Dissertation
  • The Need for Composite Concept Sets. Sigfried Gold, Harold P. Lehmann, Lisa Eskenazi, Tanner Zhang, Stephanie Hong, Richard L. Zhu, Christopher G. Chute, on behalf of the N3C Consortium. 2023 OHDSI Symposium, 2023 — PDF — OHDSI showcase
  • Augmenting the National COVID Cohort Collaborative (N3C) Dataset with Medicare and Medicaid (CMS) Data, Secure and Deidentified Clinical Dataset. Stephanie Hong, Thomas Richards, Benjamin Amor, Tim Schwab, Philip Sparks, Maya Choudhury, Saad Ljazouli, Peter Leese, Amin Manna, Christophe Roeder, Tanner Zhang, Lisa Eskenazi, Bryan Laraway, James Cavallon, Eric Kim, Shijia Zhang, Emir Amaro Syailendra, Shawn O'Neil, Davera Gabriel, Sigfried Gold, Tricia Francis, Andrew Girvin, Emily Pfaff, Anita Walden, Harold Lehmann, Melissa Haendel, Ken Gersing, Christopher G Chute. 2023 OHDSI Global Symposium, 2023 — Report — OHDSI showcase
  • ICD10 — SNOMED mapping pitfalls: Post-coordinated expressions and concept sets. Sigfried Gold, Tanner Zhang, Richard L. Zhu, Stephanie Hong, Harold P. Lehmann, Davera Gabriel, Tricia Francis, Lisa Eskenazi, Christopher G. Chute. 2022 OHDSI Symposium, Bethesda, Maryland, 2022 — Abstract — OHDSI showcase
  • Synergies between centralized and federated approaches to data quality: a report from the national COVID cohort collaborative. Pfaff ER, Girvin AT, Gabriel DL, Kostka K, Morris M, Palchuk MB, Lehmann HP, Amor B, Bissell M, Bradwell KR, Gold S, Hong SS, Loomba J, Manna A, McMurry JA, Niehaus E, Qureshi N, Walden A, Zhang XT, Zhu RL, Moffitt RA, Haendel MA, Chute CG; N3C Consortium. Journal of the American Medical Informatics Association 29(4), 2022 — DOI
  • Practices, norms, and aspirations regarding the construction, validation, and reuse of code sets in the analysis of real-world data. Sigfried Gold, Harold Lehmann, Lisa Schilling, Wayne Lutters. medRxiv, 2021 — medRxiv
  • Categorizing metadata to help mobilize computable biomedical knowledge. Brian S. Alper, Allen Flynn, Bruce E. Bray, Marisa L. Conte, Christina Eldredge, Sigfried Gold, Robert A. Greenes, Peter Haug, Kim Jacoby, Gunes Koru, James McClay, Marc L. Sainvil, Davide Sottara, Mark Tuttle, Shyam Visweswaran, Robin Ann Yurk. Learning Health Systems, 2021 — DOI
  • Electronic Health Records-Based Phenotyping. Richesson R, Wiley L, Gold S, Rasmussen L. Rethinking Clinical Trials: A Living Textbook of Pragmatic Clinical Trials, 2020 — Chapter
  • The Use of Inter-terminology Maps for the Creation and Maintenance of Value Sets. Fung KW, Xu J, Gold S. AMIA Annual Symposium proceedings, 2019, 2019 — PubMed Central
  • Sharing of Individual Participant Data from Clinical Trials: General Comparison and HIV Use Case. Mayer CS, Williams N, Gold S, Fung KW, Huser V. AMIA Annual Symposium proceedings, 2019, 2019 — PubMed Central
  • Set of derived metadata elements for comparing cohorts from human clinical trials datasets and EHR. Huser V, Mayer C, Williams N, Gold S, Fung KW. OHDSI Symposium 2019, 2019 — Poster — OHDSI showcase
  • Validation of Real World Data: Case study in hepatitis C. Mayer C, Williams N, Gold S, Fung KW, Huser V. OHDSI Symposium 2019, 2019 — Poster — Abstract — OHDSI showcase
  • Case Studies Beware! Rx and Labs return minor improvements in HIV prevalence capture for Medicare Parts D and B for 2012 to 2016. Williams N, Huser V, Mayer C, Gold S, Fung KW. OHDSI Symposium 2019, 2019 — Poster — Abstract — OHDSI showcase
  • Automated Discovery of Common Data Elements in HIV Clinical Trials Using an Interaction Network. Nick Williams, Sigfried Gold, Vojtech Huser, Kin Wah Fung, Craig S Mayer. AMIA, 2019, 2019 — Source code
  • Clinical Concept Value Sets and Interoperability in Health Data Analytics. Gold S, Batch A, McClure R, Jiang G, Kharrazi H, Saripalle R, Huser V, Weng C, Roderer N, Szarfman A, Elmqvist N, Gotz D. AMIA Annual Symposium proceedings, 2018, 480-489, 2018 — PubMed Central
  • P3 — Partition, Pivot, and Prune: Aggregated Semantic Graphs for Analyzing Medical Terminologies. Gold, Hochheiser, Boyce, Elmqvist. Visual Analytics in Healthcare, San Francisco, November 2018, 2018 — Paper — Poster
  • Community Strengthening and Knowledge Sharing Towards Systematic and Scalable Clinical Data Quality Assessment. Weng, Mosa, Ahuja, Szarfman, Solomonides, Huser, Gold, Zozus. AMIA Annual Symposium, 2018 (panel), 2018
  • Concept Sets in Secondary-Use Health Analytics. Sigfried Gold. OHDSI Community Call, July 17, 2018, 2018 — Slides
  • Visual Analytics for Ontology-Informed Data. Sigfried Gold, Niklas Elmqvist. Human-Computer Interaction Lab Symposium, University of Maryland, 2018-05-24, 2018 — Paper
  • OHDSI Development Architecture (tutorial). Frank DeFalco, Sigfried Gold, Gregory Klebanov, Lee Evans. 2017 OHDSI Symposium tutorials, October 20, 2017, 2017 — Slides — Video
  • CHRONOS: Cohort exploration through individual patient profiles. Gold, Blacketer, Sena, DeFalco. OHDSI Symposium, Washington, DC, 2016, 2016 — Poster — Abstract
  • SEEM: A Scalable Visualization for Comparing Multiple Large Sets of Attributes for Malware Analysis. Gove, Saxe, Gold, Long, Bergamo. Proceedings of the Eleventh Workshop on Visualization for Cyber Security (VizSec), Paris, France, 2014 — DOI
  • Black Hat Presentation. Black Hat USA 2014, 2014 — Slides
  • Visualizing Patterns of Drug Prescriptions with EventFlow: A Pilot Study of Asthma Medications in the Military Health System. Megan Monroe, Tamra E. Meyer, Catherine Plaisant, Rongjian Lan, Krist Wongsuphasawat, Trinka S. Coster, Sigfried Gold, Jeff Millstein, Ben Shneiderman. Workshop on Visual Analytics in Healthcare (VAHC), 2013, 2013 — Paper
  • Exploring Point and Interval Event Patterns: Display Methods and Interactive Visual Query. Megan Monroe, Krist Wongsuphasawat, Catherine Plaisant, Ben Shneiderman, Jeff Millstein, Sigfried Gold. University of Maryland HCIL Tech Report, 2012 — Paper
  • A Sorting and Classification Method for Interactive Visualization of Drug/Event Patterns across Many Patient Timelines. Gold, Xie, Taylor, Szarfman, Coster. 26th International Conference on Pharmacoepidemiology and Therapeutic Risk Management (ICPE), Brighton, UK, 2010 — Poster
  • Using Timeline Displays to Improve Medication Reconciliation. Xinxin Zhu, Sigfried Gold, Albert Lai, George Hripcsak, James J. Cimino. 2009 International Conference on eHealth, Telemedicine, and Social Medicine (eTELEMED), 2009 — DOI
  • Extracting Structured Medication Event Information from Discharge Summaries (AMIA 2008). Gold S, Elhadad N, Zhu X, Cimino JJ, Hripcsak G. AMIA Annual Symposium proceedings, 2008, 2008 — PubMed Central — PDF
  • Safety in Numbers (Kubick & Gold, GCP Journal 2008). Kubick W, Gold S. Good Clinical Practice Journal, September 2008, pp. 21-24, 2008

Software & Demos

  • Bridge2AI Standards Explorer. Interactive explorer for the Bridge2AI standards landscape — Live demo
  • dag-browser-widget. npm package: browse a DAG/polyhierarchy (cycles included) as a collapsible tree — multi-parent nodes unfold once, other parents become cross-reference links — Live demo — Source code — npm
  • OHDSI / ATLAS Patient Profile Visualization. Interactive display of patient medical history for observational research — Source code — OHDSI
  • Supergroup. Adds extreme convenience and understandability to the manipulation of Javascript data collections, especially in the context of D3.js visualization programming — Documentation — Source code — Blog article
  • TreeLike arbitrary CSV visualization in D3.js — Live demo — Documentation — Source code
  • LifeFlow and event visualization in D3.js — Live demo — Source code
  • EventFlow. Visual Analysis of Temporal Event Sequences and Advanced Strategies for Healthcare Discovery. Collaboration with University of Maryland Human Computer Interaction Lab, Ben Shneiderman, Catherine Plaisant, Megan Monroe, Krist Wongsuphasawat, and Jeff Millstein (2010 - 2013) — Paper — Video — Case study — EventFlow — HCIL