ACAlison Callahan

Alison Callahan

*This is an algorithmically generated author record based on publicly available information.

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Previous Organizations / Institutes

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Alison Callahan has a total of 211 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Development of Longitudinal, Linked Maternal-Infant Cohorts using the Epic Cosmos Electronic Health Record Dataset

    by Stephanie A. Leonard, Kevin Dysart, Alison Callahan, Sara Siadat, Jiaqi Zhang, Sara C. Handley, Krista F. Huybrechts, Irogue Igbinosa, Brian T. Bateman

    Background: Epic Cosmos is a relatively new centralized electronic health record dataset with high potential utility in perinatal epidemiologic research. Objectives: The study objectives were to develop replicable steps to create longitudinal, linked maternal-infant cohorts in Cosmos, assess completeness of key variables, evaluate potential selection bias with restrictions for longitudinal healthcare encounters, and provide an example epidemiologic analysis. Methods: We created maternal-infant cohorts by starting with live births during 2023-2024 recorded in the BirthFact data table and joining with additional data tables as needed. We selected and created variables for perinatal characteristics, common comorbidities, and routinely measured vital signs and laboratory values, and assessed variable completeness. We sequentially restricted the birth cohort for maternal-infant linkage and longitudinal healthcare from first-trimester prenatal care encounter through infant follow-up care within 12 weeks post-discharge from birth hospitalization. Finally, we conducted an example analysis of the association between high systolic blood pressure in the first trimester (≥140 mm Hg) and later onset of preeclampsia among those with chronic hypertension. Results: The total linked birth cohort included 2,624,186 pregnancies. Completeness was >90% for most variables assessed but was 77% for racial and ethnic group and 76% for body mass index at delivery. Characteristics of the cohort were similar to those reported for the entire United States birth population based on birth certificate data, including similar regional and racial-ethnic composition. Longitudinal cohort restriction requiring linked records from first trimester prenatal care through infant follow-up care reduced the cohort size to 509,148 pregnancies. However, restriction had minimal effects on cohort characteristics. In the example analysis, high systolic blood pressure was associated with increased risk of preeclampsia among those with chronic hypertension (aRR: 1.26; 95% CI: 1.22, 1.30). Conclusions: This study provides a rigorous and reproducible approach to creating longitudinal, linked maternal-infant cohorts in Epic Cosmos and the analytical findings suggest high data quality and representativeness.


  • Top Cited Papers

    Why and How to Monitor Deployed AI Systems in Health Care

    by Timothy Keyes, Alison Callahan, Abby S. Pandya, Nerissa Ambers, Juan M. Banda, Miguel Fuentes, Carlene Lugtu, Pranav Masariya, Srikar Nallan, Connor O’BRien, et al.

    Postdeployment monitoring of artificial intelligence (AI) systems in health care is essential to ensure their safety, quality, and sustained benefit - and to support governance decisions about which systems to update, modify, or decommission. Motivated by these needs, the authors developed a framework for monitoring deployed AI systems organized around three complementary principles: system integrity, performance, and impact. System integrity monitoring focuses on maximizing system uptime, detecting runtime errors, and identifying when changes to the surrounding information technology ecosystem have unintended effects. Performance monitoring focuses on maintaining accurate and equitable system behavior in the face of changing health care practices (and thus input data) over time. Impact monitoring assesses whether a deployed system continues to have value in the form of benefit to clinicians, staff, and patients. Drawing on examples of deployed AI systems at their academic medical center, the authors provide practical guidance for creating monitoring plans based on these principles that specify which metrics to measure and at what cadence, who is responsible for acting when metrics change, and what concrete follow-up actions should be taken - for both traditional and generative AI. They also discuss challenges in implementing this framework, including the effort of monitoring for health systems with limited resources, and the difficulty of incorporating data-driven monitoring practices into complex organizations where conflicting priorities and definitions of success often coexist. This framework offers a starting point for health systems seeking to ensure that AI deployments remain safe and effective over time.


  • Top Cited Papers

    Designing Clinically Useful AI: A Blueprint for Impact

    by Shyon Parsa, Timothy Keyes, Dev Dash, Danton Char, Michelle M. Mello, Alison Callahan, Margaret Ann Smith, Sinjin Lee, Thomas Wang, Heidi Salisbury, et al.


  • Open Access

    Expanding the OMOP Common Data Model to Support Perinatal Research in Network Studies

    by Alicia Abellan, Edward Burn, Nhung T. H. Trinh, Theresa Burkard, Alison Callahan, Sergio Fernández‐Bertolín, Eimir Hurley, Clara Rodriguez, Elena Segundo, Daniel R. Morales, et al.

    Objectives: The Observational Medical Outcomes Partnership common data model (OMOP‐CDM) is a useful tool for large‐scale network analysis but currently lacks a structured approach to pregnancy episodes. We aimed to develop and implement a perinatal expansion for the OMOP‐CDM to facilitate perinatal network research.Methods: We collaboratively developed a perinatal expansion with input from domain experts and stakeholders to reach consensus. The structure and vocabularies followed the OMOP‐CDM ontological framework principles. We tested the expansion using SIDIAP and Norwegian databases. We developed a diagnostics package for quality control assessment and conducted a descriptive analysis on the captured perinatal data mapped to the OMOP‐CDM.Results: The perinatal expansion consists of a pregnancy table and an infant table, each with required and optional variables incorporated into standardized vocabularies. Quality assessment of the perinatal expansion table in SIDIAP and Norwegian databases demonstrated accurate capture of perinatal characteristics. Descriptive analysis measured the number of pregnancies (SIDIAP: 646 530; Norway: 746 671), pregnancy outcomes (e.g., 0.5% stillbirths in SIDIAP and 0.4% in Norway), gestational length (median [IQR] in days, SIDIAP: 273 [56–280]; Norway: 280 [273–286]), number of infants (Norway: 758 806), and birth weight (median [IQR] in grams, Norway: 3520 [3175–3860)], among other relevant variables.Discussion and Conclusion: We developed and implemented a perinatal expansion that captures important variables for perinatal research and allows interoperability with existing tables in the OMOP‐CDM, which is expected to facilitate future network studies. The publicly available diagnostics package enables testing the implementation of the extension table and the quality and completeness of available data on pregnancy and pregnancy‐related outcomes in databases mapped to the OMOP CDM.


  • Open Access

    AI-VOICE: A Method to Measure and Incorporate Patient Utilities Into AI-Informed Healthcare Workflows

    by Keith E. Morse, Michael C. Higgins, Yichun Qian, Alison Callahan, Nigam H. Shah

    Background: Patients are important participants in their medical care, yet artificial intelligence (AI) models are used to guide care with minimal patient input. This limitation is made partially worse due to a paucity of rigorous methods to measure and incorporate patient values of the tradeoffs inherent in AI applications. This paper presents AI-VOICE (Values-Oriented Implementation and Context Evaluation), a novel method to collect patient values, or utilities, of the downstream consequences stemming from an AI model’s use to guide care. The results are then used to select the model’s risk threshold, offering a mechanism by which an algorithm can concretely reflect patient values. Methods: The entity being evaluated by AI-VOICE is an AI-informed workflow , which is composed of the patient’s health state, an action triggered by the AI model, and the benefits and harms accrued as a consequence of that action. The utilities of these workflows are measured through a survey-based, standard gamble experiment. These utilities define a patient-specific ratio of the cost of an inaccurate prediction versus the benefits of an accurate one. This ratio is mapped to the receiver-operator-characteristic curve to identify the risk threshold that reflects the patient’s values. The survey instrument is made freely available to researchers through a web-based application. Results: A demonstration of AI-VOICE is provided using a hypothetical sepsis prediction algorithm. Conclusion: AI-VOICE offers an accessible, quantitative method to incorporate patient values into AI-informed healthcare workflows.

  • Standing on FURM Ground: A Framework for Evaluating Fair, Useful, and Reliable AI Models in Health Care Systems

    by Alison Callahan, Duncan McElfresh, Juan M. Banda, Gabrielle Bunney, Danton Char, Jonathan Chen, Conor K. Corbin, Debadutta Dash, Norman L. Downing, Sneha S. Jain, et al.


  • Open Access

    A Systematic Review of Testing and Evaluation of Healthcare Applications of Large Language Models (LLMs)

    by Suhana Bedi, Yutong Liu, Lucy Orr-Ewing, Debadutta Dash, Sanmi Koyejo, Alison Callahan, Jason Alan Fries, Michael Wornow, Akshay Swaminathan, Lisa Soleymani Lehmann, et al.

    1 Importance: Large Language Models (LLMs) can assist in a wide range of healthcare-related activities. Current approaches to evaluating LLMs make it difficult to identify the most impactful LLM application areas. Objective: To summarize the current evaluation of LLMs in healthcare in terms of 5 components: evaluation data type, healthcare task, Natural Language Processing (NLP)/Natural Language Understanding (NLU) task, dimension of evaluation, and medical specialty. Data Sources: A systematic search of PubMed and Web of Science was performed for studies published between 01-01-2022 and 02-19-2024. Study Selection: Studies evaluating one or more LLMs in healthcare. Data Extraction and Synthesis: Three independent reviewers categorized 519 studies in terms of data used in the evaluation, the healthcare tasks (the what) and the NLP/NLU tasks (the how) examined, the dimension(s) of evaluation, and the medical specialty studied. Results: Only 5% of reviewed studies utilized real patient care data for LLM evaluation. The most popular healthcare tasks were assessing medical knowledge (e.g. answering medical licensing exam questions, 44.5%), followed by making diagnoses (19.5%), and educating patients (17.7%). Administrative tasks such as assigning provider billing codes (0.2%), writing prescriptions (0.2%), generating clinical referrals (0.6%) and clinical notetaking (0.8%) were less studied. For NLP/NLU tasks, the vast majority of studies examined question answering (84.2%). Other tasks such as summarization (8.9%), conversational dialogue (3.3%), and translation (3.1%) were infrequent. Almost all studies (95.4%) used accuracy as the primary dimension of evaluation; fairness, bias and toxicity (15.8%), robustness (14.8%), deployment considerations (4.6%), and calibration and uncertainty (1.2%) were infrequently measured. Finally, in terms of medical specialty area, most studies were in internal medicine (42%), surgery (11.4%) and ophthalmology (6.9%), with nuclear medicine (0.6%), physical medicine (0.4%) and medical genetics (0.2%) being the least represented. Conclusions and Relevance: Existing evaluations of LLMs mostly focused on accuracy of question answering for medical exams, without consideration of real patient care data. Dimensions like fairness, bias and toxicity, robustness, and deployment considerations received limited attention. To draw meaningful conclusions and improve LLM adoption, future studies need to establish a standardized set of LLM applications and evaluation dimensions, perform evaluations using data from routine care, and broaden testing to include administrative tasks as well as multiple medical specialties. Key Points: Question: How are healthcare applications of large language models (LLMs) currently evaluated? Findings: Studies rarely used real patient care data for LLM evaluation. Administrative tasks such as generating provider billing codes and writing prescriptions were understudied. Natural Language Processing (NLP)/Natural Language Understanding (NLU) tasks like summarization, conversational dialogue, and translation were infrequently explored. Accuracy was the predominant dimension of evaluation, while fairness, bias and toxicity assessments were neglected. Evaluations in specialized fields, such as nuclear medicine and medical genetics were rare. Meaning: Current LLM assessments in healthcare remain shallow and fragmented. To draw concrete insights on their performance, evaluations need to use real patient care data across a broad range of healthcare and NLP/NLU tasks and medical specialties with standardized dimensions of evaluation.


  • Open Access

    The Stanford Medicine data science ecosystem for clinical and translational research

    by Alison Callahan, Euan Ashley, Somalee Datta, Priyamvada Desai, Todd A Ferris, Jason A Fries, Michael Halaas, Curtis P Langlotz, Sean Mackey, José D Posada, et al.

    Objective: To describe the infrastructure, tools, and services developed at Stanford Medicine to maintain its data science ecosystem and research patient data repository for clinical and translational research. Materials and Methods: The data science ecosystem, dubbed the Stanford Data Science Resources (SDSR), includes infrastructure and tools to create, search, retrieve, and analyze patient data, as well as services for data deidentification, linkage, and processing to extract high-value information from healthcare IT systems. Data are made available via self-service and concierge access, on HIPAA compliant secure computing infrastructure supported by in-depth user training. Results: The Stanford Medicine Research Data Repository (STARR) functions as the SDSR data integration point, and includes electronic medical records, clinical images, text, bedside monitoring data and HL7 messages. SDSR tools include tools for electronic phenotyping, cohort building, and a search engine for patient timelines. The SDSR supports patient data collection, reproducible research, and teaching using healthcare data, and facilitates industry collaborations and large-scale observational studies. Discussion: Research patient data repositories and their underlying data science infrastructure are essential to realizing a learning health system and advancing the mission of academic medical centers. Challenges to maintaining the SDSR include ensuring sufficient financial support while providing researchers and clinicians with maximal access to data and digital infrastructure, balancing tool development with user training, and supporting the diverse needs of users. Conclusion: Our experience maintaining the SDSR offers a case study for academic medical centers developing data science and research informatics infrastructure.


  • Open Access

    APLUS: A Python library for usefulness simulations of machine learning models in healthcare

    by Michael Wornow, Elsie Gyang Ross, Alison Callahan, Nigam H. Shah


  • Treatment and Monitoring Variability in US Metastatic Breast Cancer Care

    by Jennifer L. Caswell-Jin, Alison Callahan, Natasha Purington, Summer S. Han, Haruka Itakura, Esther M. John, Douglas W. Blayney, George W. Sledge, Nigam H. Shah, Allison W. Kurian

    PURPOSE: Treatment and monitoring options for patients with metastatic breast cancer (MBC) are increasing, but little is known about variability in care. We sought to improve understanding of MBC care and its correlates by analyzing real-world claims data using a search engine with a novel query language to enable temporal electronic phenotyping. METHODS: Using the Advanced Cohort Engine, we identified 6,180 women who met criteria for having estrogen receptor–positive, human epidermal growth factor receptor 2–negative MBC from IBM MarketScan US insurance claims (2007-2014). We characterized treatment, monitoring, and hospice usage, along with clinical and nonclinical factors affecting care. RESULTS: We observed wide variability in treatment modality and monitoring across patients and geography. Most women received first-recorded therapy with endocrine (67%) versus chemotherapy, underwent more computed tomography (CT) (76%) than positron emission tomography-CT, and were monitored using tumor markers (58%). Nearly half (46%) met criteria for aggressive disease, which were associated with receiving chemotherapy first, monitoring primarily with CT, and more frequent imaging. Older age was associated with endocrine therapy first, less frequent imaging, and less use of tumor markers. After controlling for clinical factors, care strategies varied significantly by nonclinical factors (median regional income with first-recorded therapy and imaging type, geographic region with these and with imaging frequency and use of tumor markers; P < .0001). CONCLUSION: Variability in US MBC care is explained by patient and disease factors and by nonclinical factors such as geographic region, suggesting that treatment decisions are influenced by local practice patterns and/or resources. A search engine designed to express complex electronic phenotypes from longitudinal patient records enables the identification of variability in patient care, helping to define disparities and areas for improvement.