Development and evaluation of a common data model enabling active drug safety surveillance using disparate healthcare databases. - Stephanie J. Reisinger; Patrick B. Ryan; Donald J. O'Hara; Gregory E. Powell; Jeffery L. Painter; Edward N. Pattishall; Jonathan A. Morris (J. Am. Medical Informatics Assoc., 2010)

Validation of a common data model for active safety surveillance research. - J. Marc Overhage; Patrick B. Ryan; Christian G. Reich; Abraham G. Hartzema; Paul E. Stang (J. Am. Medical Informatics Assoc., 2012)

Evaluation of alternative standardized terminologies for medical conditions within a network of observational healthcare databases. - Christian G. Reich; Patrick B. Ryan; Paul E. Stang; Mitra Rocca (J. Biomed. Informatics, 2012)

Developing a Systematic Approach to Measure Medication Adherence. - Vivienne J. Zhu; Patrick B. Ryan; J. Marc Overhage; Paul E. Stang; Jesse Berlin (AMIA, 2013)

Massive Parallelization of Serial Inference Algorithms for a Complex Generalized Linear Model. - Marc A. Suchard; Shawn E. Simpson; Ivan Zorych; Patrick B. Ryan; David Madigan (ACM Trans. Model. Comput. Simul., 2013)

Transforming NHANES Database to the OMOP Common Data Model. - Vivienne J. Zhu; Rupa Makadia; Amy Matcho; Martijn J. Schuemie; Patrick B. Ryan (AMIA, 2014)

Big data, big results: Knowledge discovery in output from large-scale analytics. - Tyler H. McCormick; Rebecca Ferrell; Alan F. Karr; Patrick B. Ryan (Stat. Anal. Data Min., 2014)

Simulation-based Evaluation of the Generalizability Index for Study Traits. - Zhe He 001; Praveen Chandar Ravichandran; Patrick B. Ryan; Chunhua Weng (AMIA, 2015)

OHDSI: An Open-Source Platform for Observational Data Analytics and Collaborative Research. - Jon D. Duke; Frank J. DeFalco; Chris Knoll; Vojtech Huser; Richard D. Boyce; Patrick B. Ryan (AMIA, 2015)

The Value of an Open-Source Observational Research Collaboratory: Results from the OHDSI Initiative. - Jon D. Duke; George Hripcsak; Nigam Shah; Patrick B. Ryan (AMIA, 2015)

Observational Health Data Sciences and Informatics (OHDSI): Opportunities for Observational Researchers. - George Hripcsak; Jon D. Duke; Nigam H. Shah; Christian G. Reich; Vojtech Huser; Martijn J. Schuemie; Marc A. Suchard; Rae Woong Park; Ian Chi Kei Wong; Peter R. Rijnbeek; Johan van der Lei; Nicole Pratt; et al. (MedInfo, 2015)

Feasibility and utility of applications of the common data model to multiple, disparate observational health databases. - Erica A. Voss; Rupa Makadia; Amy Matcho; Qianli Ma; Chris Knoll; Martijn J. Schuemie; Frank J. DeFalco; Ajit Londhe; Vivienne J. Zhu; Patrick B. Ryan (J. Am. Medical Informatics Assoc., 2015)

Predicting health outcomes from high-dimensional longitudinal health histories using relational random forests. - Zach Shahn; Patrick B. Ryan; David Madigan (Stat. Anal. Data Min., 2015)

Ensuring Reproducibility in Observational Research: Building and Sharing Knowledge Resources in the OHDSI Network. - Jon D. Duke; Nigam H. Shah; George Hripcsak; Patrick B. Ryan (AMIA, 2016)

Big Data for Healthcare and Life Sciences: Learning Useful Insights from Imperfect Data. - Jianying Hu; Nigam H. Shah; Bradley A. Malin; Patrick B. Ryan; Anil Jain (AMIA, 2016)

Observational Health Data Sciences and Informatics (OHDSI): A Rapidly Growing International Network for Open Science and Data Analytics in Healthcare. - Jon D. Duke; George Hripcsak; Nigam Shah; Patrick B. Ryan; Vojtech Huser (CRI, 2016)

The Applicability of an EHR Phenotype for Cohort Identification. - Ning Shang; George Hripcsak; Patrick B. Ryan; Chunhua Weng (CRI, 2016)

Multivariate analysis of the population representativeness of related clinical studies. - Zhe He 001; Patrick B. Ryan; Julia Hoxha; Shuang Wang; Simona Carini; Ida Sim; Chunhua Weng (J. Biomed. Informatics, 2016)

GIST 2.0: A scalable multi-trait metric for quantifying population representativeness of individual clinical studies. - Anando Sen; Shreya Chakrabarti; Andrew Goldstein; Shuang Wang; Patrick B. Ryan; Chunhua Weng (J. Biomed. Informatics, 2016)

Hierarchical models for multiple, rare outcomes using massive observational healthcare databases. - Trevor R. Shaddox; Patrick B. Ryan; Martijn J. Schuemie; David Madigan; Marc A. Suchard (Stat. Anal. Data Min., 2016)

From Large-Scale Network Analytics to Clinical Solutions in OHDSI. - Jon D. Duke; George Hripcsak; Patrick B. Ryan; Nigam Shah (AMIA, 2017)

Criteria2Query: Automatically Transforming Clinical Research Eligibility Criteria Text to OMOP Common Data Model (CDM)-based Cohort Queries. - Chi Yuan; Patrick B. Ryan; Yixuan Guo; Peng Jin; Tian Kang; Chunhua Weng (AMIA, 2017)

The Impact of Censoring Drug Switching in Medication Adherence Measures of Chronic Single Ingredient Oral Drugs. - Vivienne J. Zhu; J. Marc Overhage; Qianli Ma; Patrick B. Ryan (MedInfo, 2017)

Large-scale adverse effects related to treatment evidence standardization (LAERTES): an open scalable system for linking pharmacovigilance evidence sources with clinical data. - Richard D. Boyce; Erica A. Voss; Vojtech Huser; Lee Evans; Christian G. Reich; Jon D. Duke; Nicholas P. Tatonetti; Tal Lorberbaum; Michel Dumontier; Manfred Hauben; Magnus Wallberg; Lili Peng; et al. (J. Biomed. Semant., 2017)

Procedure prediction from symbolic Electronic Health Records via time intervals analytics. - Robert Moskovitch; Fernanda Polubriaginof; Aviram Weiss; Patrick B. Ryan; Nicholas P. Tatonetti (J. Biomed. Informatics, 2017)

Accuracy of an automated knowledge base for identifying drug adverse reactions. - Erica A. Voss; Richard D. Boyce; Patrick B. Ryan; Johan van der Lei; Peter R. Rijnbeek; Martijn J. Schuemie (J. Biomed. Informatics, 2017)

Treatment Pathways in Patients with Cancer Using a Large-scale Observational Data Network. - Ruijun Chen; Patrick B. Ryan; Karthik Natarajan; Thomas Falconer; Christian G. Reich; Rohit Vashisht; Nigam Shah; George Hripcsak (AMIA, 2018)

Uncovering exposures responsible for birth season - disease effects: a global study. - Mary Regina Boland; Pradipta Parhi; Li Li 062; Riccardo Miotto; Robert J. Carroll; Usman Iqbal; Phung-Anh (Alex) Nguyen; Martijn J. Schuemie; Seng Chan You; Donahue Smith; Sean D. Mooney; Patrick B. Ryan; et al. (J. Am. Medical Informatics Assoc., 2018)

Decentralized and reproducible geocoding and characterization of community and environmental exposures for multisite studies. - Cole Brokamp; Chris Wolfe; Todd Lingren; John Harley; Patrick B. Ryan (J. Am. Medical Informatics Assoc., 2018)

Effect of vocabulary mapping for conditions on phenotype cohorts. - George Hripcsak; Matthew E. Levine; Ning Shang; Patrick B. Ryan (J. Am. Medical Informatics Assoc., 2018)

Design and implementation of a standardized framework to generate and evaluate patient-level prediction models using observational healthcare data. - Jenna Marie Reps; Martijn J. Schuemie; Marc A. Suchard; Patrick B. Ryan; Peter R. Rijnbeek (J. Am. Medical Informatics Assoc., 2018)

The representativeness of eligible patients in type 2 diabetes trials: a case study using GIST 2.0. - Anando Sen; Andrew Goldstein; Shreya Chakrabarti; Ning Shang; Tian Kang; Anil Yaman; Patrick B. Ryan; Chunhua Weng (J. Am. Medical Informatics Assoc., 2018)

Learning Across a Healthcare Data Network to Improve Model Robustness and Evidence Reliability. - Noémie Elhadad; Iñigo Urteaga; Alison Callahan; Jenna Reps; Patrick B. Ryan (AMIA, 2019)

Challenges with quality of race and ethnicity data in observational databases. - Fernanda C. Polubriaginof; Patrick B. Ryan; Hojjat Salmasian; Andrea W. Shapiro; Adler J. Perotte; Monika M. Safford; George Hripcsak; Shaun Smith; Nicholas P. Tatonetti; David K. Vawdrey (J. Am. Medical Informatics Assoc., 2019)

Criteria2Query: a natural language interface to clinical databases for cohort definition. - Chi Yuan; Patrick B. Ryan; Casey N. Ta; Yixuan Guo; Ziran Li; Jill Hardin; Rupa Makadia; Peng Jin; Ning Shang; Tian Kang; Chunhua Weng (J. Am. Medical Informatics Assoc., 2019)

Supplementing claims data analysis using self-reported data to develop a probabilistic phenotype model for current smoking status. - Jenna Marie Reps; Peter R. Rijnbeek; Patrick B. Ryan (J. Biomed. Informatics, 2019)

PheValuator: Development and evaluation of a phenotype algorithm evaluator. - Joel N. Swerdel; George Hripcsak; Patrick B. Ryan (J. Biomed. Informatics, 2019)

Evaluation of Large-scale Propensity Score Modeling and Covariate Balance on Potential Unmeasured Confounding in Observational Research. - Ruijun Chen; Martijn J. Schuemie; Marc A. Suchard; Anna Ostropolets; Linying Zhang; Patrick B. Ryan; George Hripcsak (AMIA, 2020)

Characterizing database granularity using SNOMED-CT hierarchy. - Anna Ostropolets; Christian G. Reich; Patrick B. Ryan; Chunhua Weng; Anthony Molinaro; Frank J. DeFalco; Jitendra Jonnagaddala; Siaw-Teng Liaw; Hokyun Jeon; Rae Woong Park; Matthew E. Spotnitz; Karthik Natarajan; et al. (AMIA, 2020)

Characterization and Comparison of Embedding Algorithms for Phenotyping across a Network of Observational Databases. - Chao Pang; Ruijun Chen; Harry Reyes Nieva; Krishna Kalluri; Tony Sun; Xinzhuo Jiang; Victor Alfonso Rodriguez; Patrick B. Ryan; Karthik Natarajan (AMIA, 2020)

Phenotype Concept Set Construction from Concept Pair Likelihoods. - Victor Alfonso Rodriguez; Tony Sun; Phyllis Thangaraj; Chao Pang; Krishna Kalluri; Xinzhuo Jiang; Karthik Natarajan; Patrick B. Ryan; Anna Ostropolets; Ruijun Chen (AMIA, 2020)

Contemporary Use of Real World Data for Clinical Trial Conduct. - James R. Rogers; Junghwan Lee; Ziheng Zhou; Patrick B. Ryan; George Hripcsak; Chunhua Weng (AMIA, 2020)

How little data do we need for patient-level prediction? - Luis H. John; Jan A. Kors; Jenna Marie Reps; Patrick B. Ryan; Peter R. Rijnbeek (CoRR, 2020)

Large-scale evidence generation and evaluation across a network of databases (LEGEND): assessing validity using hypertension as a case study. - Martijn J. Schuemie; Patrick B. Ryan; Nicole Pratt; Ruijun Chen; Seng Chan You; Harlan M. Krumholz; David Madigan; George Hripcsak; Marc A. Suchard (J. Am. Medical Informatics Assoc., 2020)

Principles of Large-scale Evidence Generation and Evaluation across a Network of Databases (LEGEND). - Martijn J. Schuemie; Patrick B. Ryan; Nicole Pratt; Ruijun Chen; Seng Chan You; Harlan M. Krumholz; David Madigan; George Hripcsak; Marc A. Suchard (J. Am. Medical Informatics Assoc., 2020)

Adapting electronic health records-derived phenotypes to claims data: Lessons learned in using limited clinical data for phenotyping. - Anna Ostropolets; Christian G. Reich; Patrick B. Ryan; Ning Shang; George Hripcsak; Chunhua Weng (J. Biomed. Informatics, 2020)

Translating evidence into practice: eligibility criteria fail to eliminate clinically significant differences between real-world and study populations. - Amelia J. Averitt; Chunhua Weng; Patrick B. Ryan; Adler J. Perotte (npj Digit. Medicine, 2020)

PHenotype Observed Entity Baseline Endorsements (PHOEBE) - recommender system for concept selection in phenotype algorithm development. - Anna Ostropolets; Patrick B. Ryan; George Hripcsak (AMIA, 2021)

Increasing trust in real-world evidence through evaluation of observational data quality. - Clair Blacketer; Frank J. DeFalco; Patrick B. Ryan; Peter R. Rijnbeek (J. Am. Medical Informatics Assoc., 2021)

Towards clinical data-driven eligibility criteria optimization for interventional COVID-19 clinical trials. - Jae Hyun Kim; Casey N. Ta; Cong Liu 020; Cynthia Sung 002; Alex M. Butler; Latoya A. Stewart; Lyudmila Ena; James R. Rogers; Junghwan Lee; Anna Ostropolets; Patrick B. Ryan; Hao Liu 054; et al. (J. Am. Medical Informatics Assoc., 2021)

Data Consult Service: Can we use observational data to address immediate clinical needs? - Anna Ostropolets; Philip Zachariah; Patrick B. Ryan; Ruijun Chen; George Hripcsak (J. Am. Medical Informatics Assoc., 2021)

Erratum to: Large-Scale Evidence Generation and Evaluation across a Network of Databases (LEGEND): Assessing Validity Using Hypertension as a Case Study. - Martijn J. Schuemie; Patrick B. Ryan; Nicole Pratt; Ruijun Chen; Seng Chan You; Harlan M. Krumholz; David Madigan; George Hripcsak; Marc A. Suchard (J. Am. Medical Informatics Assoc., 2021)

From clinical trials to clinical practice: How long are drugs tested and then used by patients? - Chi Yuan; Patrick B. Ryan; Casey N. Ta; Jae Hyun Kim; Ziran Li; Chunhua Weng (J. Am. Medical Informatics Assoc., 2021)

Design matters in patient-level prediction: evaluation of a cohort vs. case-control design when developing predictive models in observational healthcare datasets. - Jenna Marie Reps; Patrick B. Ryan; Peter R. Rijnbeek; Martijn J. Schuemie (J. Big Data, 2021)

A conceptual framework for external validity. - Amelia J. Averitt; Patrick B. Ryan; Chunhua Weng; Adler J. Perotte (J. Biomed. Informatics, 2021)

An empirical analysis of dealing with patients who are lost to follow-up when developing prognostic models using a cohort design. - Jenna Marie Reps; Peter R. Rijnbeek; Alana Cuthbert; Patrick B. Ryan; Nicole Pratt; Martijn J. Schuemie (BMC Medical Informatics Decis. Mak., 2021)

Phenotyping in distributed data networks: selecting the right codes for the right patients. - Anna Ostropolets; Patrick B. Ryan; George Hripcsak (AMIA, 2022)

Ontologizing Health Systems Data at Scale: Making Translational Discovery a Reality. - Tiffany J. Callahan; Adrianne L. Stefanski; Jordan M. Wyrwa; Chenjie Zeng; Anna Ostropolets; Juan M. Banda; William A. Baumgartner Jr.; Richard D. Boyce; Elena Casiraghi; Ben D. Coleman; Janine H. Collins; Sara J. Deakyne Davies; et al. (CoRR, 2022)

Logistic regression models for patient-level prediction based on massive observational data: Do we need all data? - Luis H. John; Jan A. Kors; Jenna Marie Reps; Patrick B. Ryan; Peter R. Rijnbeek (Int. J. Medical Informatics, 2022)

PheValuator 2.0: Methodological improvements for the PheValuator approach to semi-automated phenotype algorithm evaluation. - Joel N. Swerdel; Martijn J. Schuemie; Gayle Murray; Patrick B. Ryan (J. Biomed. Informatics, 2022)

Adaptation and validation of a coding algorithm for the Charlson Comorbidity Index in administrative claims data using the SNOMED CT standardized vocabulary. - Stephen P. Fortin; Jenna Reps; Patrick B. Ryan (BMC Medical Informatics Decis. Mak., 2022)

Learning patient-level prediction models across multiple healthcare databases: evaluation of ensembles for increasing model transportability. - Jenna Marie Reps; Ross D. Williams; Martijn J. Schuemie; Patrick B. Ryan; Peter R. Rijnbeek (BMC Medical Informatics Decis. Mak., 2022)

An Open-Source Knowledge Graph Ecosystem for the Life Sciences. - Tiffany J. Callahan; Ignacio J. Tripodi; Adrianne L. Stefanski; Luca Cappelletti; Sanya Bathla Taneja; Jordan M. Wyrwa; Elena Casiraghi; Nicolas A. Matentzoglu; Justin T. Reese; Jonathan C. Silverstein; Charles Tapley Hoyt; Richard D. Boyce; et al. (CoRR, 2023)

Ontologizing health systems data at scale: making translational discovery a reality. - Tiffany J. Callahan; Adrianne L. Stefanski; Jordan M. Wyrwa; Chenjie Zeng; Anna Ostropolets; Juan M. Banda; William A. Baumgartner Jr.; Richard D. Boyce; Elena Casiraghi; Ben D. Coleman; Janine H. Collins; Sara J. Deakyne Davies; et al. (npj Digit. Medicine, 2023)

A standardized framework for risk-based assessment of treatment effect heterogeneity in observational healthcare databases. - Alexandros Rekkas; David van Klaveren; Patrick B. Ryan; Ewout W. Steyerberg; David M. Kent; Peter R. Rijnbeek (npj Digit. Medicine, 2023)

Reproducible variability: assessing investigator discordance across 9 research teams attempting to reproduce the same observational study. - Anna Ostropolets; Yasser Albogami; Mitchell Conover; Juan M. Banda; William A. Baumgartner Jr.; Clair Blacketer; Priyamvada Desai; Scott L. DuVall; Stephen P. Fortin; James P. Gilbert; Asieh Golozar; Joshua Ide; et al. (J. Am. Medical Informatics Assoc., 2023)

Representing and utilizing clinical textual data for real world studies: An OHDSI approach. - Vipina Kuttichi Keloth; Juan M. Banda; Michael J. Gurley; Paul M. Heider; Georgina Kennedy; Hongfang Liu; Feifan Liu; Timothy Miller 002; Karthik Natarajan; Olga V. Patterson; Yifan Peng 002; Kalpana Raja; et al. (J. Biomed. Informatics, 2023)

Padé approximant meets federated learning: A nearly lossless, one-shot algorithm for evidence synthesis in distributed research networks with rare outcomes. - Qiong Wu; Martijn J. Schuemie; Marc A. Suchard; Patrick B. Ryan; George Hripcsak; Charles A. Rohde; Yong Chen 016 (J. Biomed. Informatics, 2023)

Scalable and interpretable alternative to chart review for phenotype evaluation using standardized structured data from electronic health records. - Anna Ostropolets; George Hripcsak; Syed A Husain; Lauren R. Richter; Matthew E. Spotnitz; Ahmed Elhussein; Patrick B. Ryan (J. Am. Medical Informatics Assoc., 2023)

Correction to: Adaptation and validation of a coding algorithm for the Charlson Comorbidity Index in administrative claims data using the SNOMED CT standardized vocabulary. - Stephen P. Fortin; Jenna Reps; Patrick B. Ryan (BMC Medical Informatics Decis. Mak., 2023)

OHDSI Standardized Vocabularies - a large-scale centralized reference ontology for international data harmonization. - Christian G. Reich; Anna Ostropolets; Patrick B. Ryan; Peter R. Rijnbeek; Martijn J. Schuemie; Alexander Davydov; Dmitry Dymshyts; George Hripcsak (J. Am. Medical Informatics Assoc., 2024)

Evaluation of the impact of defining observable time in real-world data on outcome incidence. - Clair Blacketer; Frank J. DeFalco; Mitchell M. Conover; Patrick B. Ryan; Martijn J. Schuemie; Peter R. Rijnbeek (J. Am. Medical Informatics Assoc., 2025)

Objective study validity diagnostics: a framework requiring pre-specified, empirical verification to increase trust in the reliability of real-world evidence. - Mitchell Conover; Patrick B. Ryan; Yong Chen 016; Marc A. Suchard; George Hripcsak; Martijn J. Schuemie (J. Am. Medical Informatics Assoc., 2025)

CLEAR: A vision to support clinical evidence lifecycle with continuous learning. - Yilu Fang; Gongbo Zhang; Fangyi Chen; George Hripcsak; Yifan Peng 002; Patrick B. Ryan; Chunhua Weng (J. Biomed. Informatics, 2025)

Evaluating the Bias, type I error and statistical power of the prior Knowledge-Guided integrated likelihood estimation (PIE) for bias reduction in EHR based association studies. - Naimin Jing; Yiwen Lu; Jiayi Tong; James Weaver; Patrick B. Ryan; Hua Xu 001; Yong Chen 016 (J. Biomed. Informatics, 2025)

Standardized patient profile review using large language models for case adjudication in observational research. - Martijn J. Schuemie; Anna Ostropolets; Aleh Zhuk; Uladzislau Korsik; Seung In Seo; Marc A. Suchard; George Hripcsak; Patrick B. Ryan (npj Digit. Medicine, 2025)