Michael A. Pfeffer, MD, FACP serves as Chief Information Officer and Associate Dean for Stanford Health Care and Stanford University School of Medicine. Michael oversees Technology and Digital Solutions (TDS), responsible for providing world class technology solutions to Stanford Health Care and School of Medicine, enabling new opportunities for groundbreaking research, teaching, and compassionate care across two hospitals and over 150 clinics. TDS supports Stanford Medicine’s mission to improve human health through discovery and care and strategic priorities to be value focused, digitally driven, and uniquely Stanford.

Michael is a Clinical Professor in the Department of Medicine and Division of Hospital Medicine with a joint appointment in the center for Biomedical Research (BMIR) in Stanford University School of Medicine. As such, Michael continues to provide clinical care as a Hospitalist Physician as well as teaching medical students and residents on the medicine inpatient wards.

Prior to joining Stanford Medicine, Michael served as the Assistant Vice Chancellor and Chief Information Officer for UCLA Health Sciences. During his tenure, Michael served as the lead physician for the largest electronic health record “big bang” go-live of its time, encompassing over 26,000 users. Michael subsequently became the first Chief Medical Informatics Officer for UCLA Health before transitioning into the Chief Information Officer position. Under his leadership, UCLA Health IT achieved numerous industry awards including the HIMSS Analytics Stage 7 Inpatient, Ambulatory, and Analytics Certifications; the Most Wired designation for eight consecutive years; US News & World Report’s Most Connected Hospitals; the Top Master’s in Healthcare Administration 30 Most Technologically Advanced Hospitals in the World; and the prestigious HIMSS Davies Award. Michael also implemented of one of the first ACGME-accredited Clinical Informatics Fellowship Programs and served as its Associate Program Director.

Michael has lectured worldwide on health information technology; served on the national HIMSS Physician Committee and as a HIMSS Stage 7 international site surveyor; and has published numerous peer-reviewed articles on health IT. Michael was featured in Becker’s Hospital Review as 10 physician CIOs to know and 12 standout healthcare CIOs and was one of LA’s top doctors in Los Angeles Magazine.

Clinical Focus

  • Internal Medicine
  • Medical Informatics
  • Hospitalists

Academic Appointments

  • Clinical Professor, Medicine

Administrative Appointments

  • Chief Information Officer, Stanford Health Care and Stanford University School of Medicine (2021 - Present)
  • Associate Dean, Stanford University School of Medicine (2021 - Present)

Professional Education

  • Board Certification: American Board of Preventive Medicine, Clinical Informatics (2015)
  • Board Certification: American Board of Internal Medicine, Internal Medicine (2007)
  • Residency: UCLA GME Office (2007) CA
  • Medical Education: Cornell University School of Medicine Registrar (2004) NY
  • Bachelor of Science, Brown University, Chemical Engineering (2000)

All Publications

  • Lower Severe Acute Respiratory Syndrome Coronavirus 2 Viral Shedding Following Coronavirus Disease 2019 Vaccination Among Healthcare Workers in Los Angeles, California OPEN FORUM INFECTIOUS DISEASES Adamson, P. C., Pfeffer, M. A., Arboleda, V. A., Garner, O. B., de St Maurice, A., von Bredow, B., Flint, J., Kruglyak, L., Currier, J. S. 2021; 8 (11)
  • Low prevalence (0.13%) of COVID-19 infection in asymptomatic pre-operative/pre-procedure patients at a large, academic medical center informs approaches to perioperative care SURGERY Singer, J. S., Cheng, E. M., Murad, D. A., Maurice, A., Hines, O., Uslan, D. Z., Garner, O., Pregler, J., Bukata, S. V., Pfeffer, M. A., Cherry, R. A. 2020; 168 (6): 980-986


    The coronavirus disease 2019 (COVID-19) pandemic has resulted in reduced performance of elective surgeries and procedures at medical centers across the United States. Awareness of the prevalence of asymptomatic disease is critical for guiding safe approaches to operative/procedural services. As COVID-19 polymerase chain reaction (PCR) testing has been limited largely to symptomatic patients, health care workers, or to those in communal care centers, data regarding asymptomatic viral disease carriage are limited.In this retrospective observational case series evaluating UCLA Health patients enrolled in pre-operative/pre-procedure protocol COVID-19 reverse transcriptase (RT)-PCR testing between April 7, 2020 and May 21, 2020, we determine the prevalence of COVID-19 infection in asymptomatic patients scheduled for surgeries and procedures.Primary outcomes include the prevalence of COVID-19 infection in this asymptomatic population. Secondary data analysis includes overall population testing results and population demographics. Eighteen of 4,751 (0.38%) patients scheduled for upcoming surgeries and high-risk procedures had abnormal (positive/inconclusive) COVID-19 RT-PCR testing results. Six of 18 patients were confirmed asymptomatic and had positive test results. Four of 18 were confirmed asymptomtic and had inconclusive results. Eight of 18 had positive results in the setting of recent symptoms or known COVID-19 infection. The prevalence of asymptomatic COVID-19 infection was 0.13%. More than 90% of patients had residential addresses within a 67-mile geographic radius of our medical center, the median age was 58, and there was equal male/female distribution.These data demonstrating low levels (0.13% prevalence) of COVID-19 infection in an asymptomatic population of patients undergoing scheduled surgeries/procedures in a large urban area have helped to inform perioperative protocols during the COVID-19 pandemic. Testing protocols like ours may prove valuable for other health systems in their approaches to safe procedural practices during COVID-19.

    View details for DOI 10.1016/j.surg.2020.07.048

    View details for Web of Science ID 000594548300004

    View details for PubMedID 33008615

    View details for PubMedCentralID PMC7427530

  • Radiology's Information Architecture Could Migrate to One Emulating That of Smartphones JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Enzmann, D. R., Arnold, C. W., Zaragoza, E., Siegel, E., Pfeffer, M. A. 2020; 17 (10): 1299-1306


    Diagnostic radiology (DxR), having had successful serial co-evolutions with imaging equipment and PACS, is faced with another. With a backdrop termed "globotics transition," it should create an IT and informatics infrastructure capable of integrating artificial intelligence (AI) into current critical communication functions of PACS and incorporating functions currently residing in balkanized products. DxR will face the challenge of adopting sustaining and disruptive AI innovations simultaneously. In this co-evolution, a major selection force for AI will be increasing the flow of information and patients; "increasing" means faster flow over larger areas defined by geography and content. Larger content includes a broader spectrum of imaging and nonimaging information streams that facilitate medical decision making. Evolution to faster flow will gravitate toward a hierarchical IT architecture consisting of many small channels feeding into fewer larger channels, something potentially difficult for current PACS. Smartphone-like architecture optimized for communication and integration could provide a large-channel backbone and many smaller feeding channels for basic functions, as well as those needing to innovate rapidly. New, more flexible architectures stimulate market competition in which DxR could act as an artificial selection force to influence development of faster increased flow in current PACS companies, in disruptors such as consolidated AI companies, or in entirely new entrants like Apple or Google. In this co-evolution, DxR should be able to stimulate design of a modern communication medium that increases the flow of information and decreases the time and energy necessary to absorb it, thereby creating even more indispensable clinical value for itself.

    View details for DOI 10.1016/j.jacr.2020.03.032

    View details for Web of Science ID 000577970400018

    View details for PubMedID 32387372

  • Excess Patient Visits for Cough and Pulmonary Disease at a Large US Health System in the Months Prior to the COVID-19 Pandemic: Time-Series Analysis JOURNAL OF MEDICAL INTERNET RESEARCH Elmore, J. G., Wang, P., Kerr, K. F., Schriger, D. L., Morrison, D. E., Brookmeyer, R., Pfeffer, M. A., Payne, T. H., Currier, J. S. 2020; 22 (9): e21562


    Accurately assessing the regional activity of diseases such as COVID-19 is important in guiding public health interventions. Leveraging electronic health records (EHRs) to monitor outpatient clinical encounters may lead to the identification of emerging outbreaks.The aim of this study is to investigate whether excess visits where the word "cough" was present in the EHR reason for visit, and hospitalizations with acute respiratory failure were more frequent from December 2019 to February 2020 compared with the preceding 5 years.A retrospective observational cohort was identified from a large US health system with 3 hospitals, over 180 clinics, and 2.5 million patient encounters annually. Data from patient encounters from July 1, 2014, to February 29, 2020, were included. Seasonal autoregressive integrated moving average (SARIMA) time-series models were used to evaluate if the observed winter 2019/2020 rates were higher than the forecast 95% prediction intervals. The estimated excess number of visits and hospitalizations in winter 2019/2020 were calculated compared to previous seasons.The percentage of patients presenting with an EHR reason for visit containing the word "cough" to clinics exceeded the 95% prediction interval the week of December 22, 2019, and was consistently above the 95% prediction interval all 10 weeks through the end of February 2020. Similar trends were noted for emergency department visits and hospitalizations starting December 22, 2019, where observed data exceeded the 95% prediction interval in 6 and 7 of the 10 weeks, respectively. The estimated excess over the 3-month 2019/2020 winter season, obtained by either subtracting the maximum or subtracting the average of the five previous seasons from the current season, was 1.6 or 2.0 excess visits for cough per 1000 outpatient visits, 11.0 or 19.2 excess visits for cough per 1000 emergency department visits, and 21.4 or 39.1 excess visits per 1000 hospitalizations with acute respiratory failure, respectively. The total numbers of excess cases above the 95% predicted forecast interval were 168 cases in the outpatient clinics, 56 cases for the emergency department, and 18 hospitalized with acute respiratory failure.A significantly higher number of patients with respiratory complaints and diseases starting in late December 2019 and continuing through February 2020 suggests community spread of SARS-CoV-2 prior to established clinical awareness and testing capabilities. This provides a case example of how health system analytics combined with EHR data can provide powerful and agile tools for identifying when future trends in patient populations are outside of the expected ranges.

    View details for DOI 10.2196/21562

    View details for Web of Science ID 000579497400005

    View details for PubMedID 32791492

    View details for PubMedCentralID PMC7485935

  • Cybersecurity implications for hospital quality HEALTH SERVICES RESEARCH Dameff, C., Pfeffer, M. A., Longhurst, C. A. 2019; 54 (5): 969-970

    View details for DOI 10.1111/1475-6773.13202

    View details for Web of Science ID 000485290700001

    View details for PubMedID 31506957

    View details for PubMedCentralID PMC6736916

  • Physicians Voluntarily Using an EHR-Based CDS Tool Improved Patients' Guideline-Related Statin Prescription Rates: A Retrospective Cohort Study APPLIED CLINICAL INFORMATICS Chang, T. S., Buchipudi, A., Fonarow, G. C., Pfeffer, M. A., Singer, J. S., Cheng, E. M. 2019; 10 (3): 421-445


    In 2013, the American College of Cardiology (ACC) and the American Heart Association (AHA) released a revised guideline on statin therapy initiation. The guideline included a 10-year risk calculation based on regression modeling, which made hand calculation infeasible. Compliance to the guideline has been suboptimal, as many patients were recommended but not prescribed statin therapy. Clinical decision support (CDS) tools may improve statin guideline compliance. Few statin guideline CDS tools evaluated clinical outcome.We determined if use of a CDS tool, the statin macro, was associated with increased 2013 ACC/AHA statin guideline compliance at the level of statin prescription versus no statin prescription. We did not determine if each patient's statin prescription met ACC/AHA 2013 therapy intensity recommendations (high vs. moderate vs. low).The authors developed a clinician-initiated, EHR-embedded statin macro command ("statin macro") that displayed the 2013 ACC/AHA statin guideline recommendation in the electronic health record documentation. We included patients who had a primary care visit during the study period (January 1-June 30, 2016), were eligible for statin therapy based on the ACC/AHA guideline prior to the study period, and were not prescribed statin therapy prior to the study period. We tested the association of macro usage and statin therapy prescription during the study period using relative risk and mixed effect logistic regression.Subjects included 11,877 patients seen in primary care, who were retrospectively recommended statin therapy at study initiation based on the ACC/AHA guideline, but who had not received statin therapy. During the study period, 125 clinicians used the statin macro command for 389 of the 11,877 patients (3.2%). Of the 389 patients for whom that statin macro was used, 108 patients (28%) had a statin prescribed during the study period. Of the 11,488 for whom the statin macro was not used, 1,360 (13%) patients received a clinician-prescribed statin (relative risk 2.3, p < 0.001). Controlling for patient covariates and clinicians, statin macro usage was significantly associated with statin therapy prescription (odds ratio 2.86, p < 0.001).Although the statin macro had low uptake, its use was associated with a greater rate of statin prescriptions (dosage not determined) for patients whom 2013 ACC/AHA guidelines required statin therapy.

    View details for DOI 10.1055/s-0039-1692186

    View details for Web of Science ID 000482343000005

    View details for PubMedID 31216590

    View details for PubMedCentralID PMC6584145

  • Feasibility study of an EHR-integrated mobile shared decision making application INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS Day, F. C., Pourhomayoun, M. B., Keeves, D., Lees, A. F., Sarrafzadeh, M., Bell, D., Pfeffer, M. A. 2019; 124: 24-30


    Integrating mobile applications (apps) into users' standard electronic health record (EHR) workflows may be valuable, especially for apps that both read and write data. This report details the lessons learned during the integration of a patient decision aid - prostate specific antigen (PSA) testing for prostate cancer screening - into our users' standard EHR workflow for a small usability assessment.This feasibility study included two steps. First we enabled realtime, secure bidirectional data exchange between the mobile app and EHR for 14 data elements, and second we pilot tested the production environment app with 9 primary care patients aged 60-65 years. Our primary usability metric was a net promoter score (NPS), based on users' recommendation of the app to a friend or family member; we also assessed the proportion of users who 1) updated their prostate cancer risk factor information present in the EHR and 2) submitted more than one unique response regarding their preference to have PSA testing.The seven web services necessary to read and write data required considerable configuration, but successfully delivered risk factor-specific educational content and recorded patients' values and decision preference directly within the EHR. Seven of the 9 patients (78%) would recommend this app to a friend/family member (NPS = 55.6%), one patient used the app to update risk factor information, and 4/9 (44%) changed their decision preference while using the app.It is feasible to implement a decision aid directly into users' standard EHR workflow for limited usability testing. Broad scale implementation may have a positive effect on patient engagement and improve shared decision making, but several challenges exist with proprietary EHR vendor application programming interfaces (API)s.

    View details for DOI 10.1016/j.ijmedinf.2019.01.008

    View details for Web of Science ID 000458863600004

    View details for PubMedID 30784423

  • Impact of Open Access to Physician Notes on Radiation Oncology Patients: Results from an Exploratory Survey PRACTICAL RADIATION ONCOLOGY Shaverdian, N., Chang, E. M., Chu, F., Morasso, E., Pfeffer, M. A., Cheng, E. M., Wu, A., McCloskey, S. A., Raldow, A. C., Steinberg, M. L. 2019; 9 (2): 102-107


    There is an increasing effort to allow patients open access to their physician notes through electronic medical record portals. However, limited data exist on the impact of such access on oncology patients, and concerns remain regarding potential harms. Therefore, we determined the baseline perceptions and impact of open access to oncology notes on radiation oncology patients.Patients receiving radiation therapy were provided instructional materials on accessing oncology notes at the time of their initial evaluation. Patients were prospectively surveyed to evaluate baseline interest and expectations before access and to determine the actual usage and impact at the end of their radiation treatment course.A total of 220 patients were surveyed; 136 (62%) completed the baseline survey, of which 88 (40%) completed the final survey. The majority of participants were age >60 years (n = 83; 61%), and 70 were male (51%). Before accessing the notes, the majority of patients agreed that open access to oncology notes would improve understanding of diagnosis (99%), understanding of treatment side effects (98%), reassurance about treatment goals (96%), and communication with family (99%). All patients who accessed the notes found them to be useful. After accessing the notes, approximately 96%, 94%, and 96% of patients reported an improved understanding of their diagnosis, an improved understanding of treatment side effects, and feeling more reassured about their treatment, respectively. Approximately 11%, 6%, and 4% of patients noted increased worry, increased confusion, and finding information they now regret reading, respectively. Patient age, sex, and specific cancer diagnoses were not predictive of experiencing negative effects from accessing the notes.Radiation oncology patients have a strong interest in open access to their physician notes, and the majority of patients expect and actually report meaningful benefits. These data support strategies to allow more patients with cancer access to their physicians' notes.

    View details for DOI 10.1016/j.prro.2018.10.004

    View details for Web of Science ID 000460044800029

    View details for PubMedID 30342179

  • How Patients Use a Patient Portal: An Institutional Case Study of Demographic and Usage Patterns APPLIED CLINICAL INFORMATICS Tsai, R., Bell, E. J., Woo, H., Baldwin, K., Pfeffer, M. A. 2019; 10 (1): 96-102


    Given the widespread electronic health record adoption, there is increasing interest to leverage patient portals to improve care.To determine characteristics of patient portal users and the activities they accessed in the patient portal.We performed a retrospective analysis of patient portal usage at University of California, Los Angeles, Health from July 2014 to May 2015. A total dataset of 505,503 patients was compiled with 396,303 patients who did not register for the patient portal and 109,200 patients who registered for a patient portal account. We compared patients who did not register for the online portal to the top 75th percentile of users based on number of logins, which was done to exclude those who only logged in to register. Finally, to avoid doing statistical analysis on too large of a sample and overpower the analysis, we performed statistical tests on a random sample of 300 patients in each of the two groups.Patient portal users tended to be older (49.45 vs. 46.22 years in the entire sample, p = 0.008 in the random sample) and more likely female (62.59 vs. 54.91% in the entire sample, p = 0.035 in the random sample). Nonusers had more monthly emergency room (ER) visits on average (0.047 vs. 0.014, p < 0.001). The most frequently accessed activity on the portal was viewing laboratory results (79.7% of users looked at laboratory results).There are differences between patient portal users and nonusers, and further understanding of these differences can serve as foundation for further investigation and possible interventions to drive patient engagement and health outcomes.

    View details for DOI 10.1055/s-0038-1677528

    View details for Web of Science ID 000459170000002

    View details for PubMedID 30727003

    View details for PubMedCentralID PMC6365289

  • Characteristics of the National Applicant Pool for Clinical Informatics Fellowships (2016-2017). AMIA ... Annual Symposium proceedings. AMIA Symposium Dell, D. S., Baldwin, K., Bell, E. J., Lehmann, C. U., Webber, E. C., Mohan, V., Leu, M. G., Hofmann, J. M., Kaelber, D. C., Landman, A. B., Hron, J., Silverman, H. D., Levy, B., Elkin, P. L., Poon, E., Luberti, A. A., Finnell, J. T., Safran, C., Palma, J. P., Forman, B. H., Kileen, J., Arvin, D., Pfeffer, M. 2018; 2018: 225–31


    We conducted a national study to assess the numbers and diversity of applicants for 2016 and 2017 clinical informatics fellowship positions. In each year, we collected data on the number of applications that programs received from candidates who were ultimately successful vs. unsuccessful. In 2017, we also conducted an anonymous applicant survey. Successful candidates applied to an average of 4.2 and 5.5 programs for 2016 and 2017, respectively. In the survey, unsuccessful candidates reported applying to fewer programs. Assuming unsuccessful candidates submitted between 2-5 applications each, the total applicant pool numbered 42-69 for 2016 (competing for 24 positions) and 52-85 for 2017 (competing for 30 positions). Among survey respondents (n=33), 24% were female, 1 was black and none were Hispanic. We conclude that greater efforts are needed to enhance interest in clinical informatics among medical students and residents, particularly among women and members of underrepresented minority groups.

    View details for PubMedID 30815060

  • The UCLA Health Resident Informaticist Program - A Novel Clinical Informatics Training Program JOURNAL OF THE AMERICAN MEDICAL INFORMATICS ASSOCIATION Singer, J. S., Cheng, E. M., Baldwin, K., Pfeffer, M. A., UCLA Hlth Phys Informaticist Comm 2017; 24 (4): 832-840


    Few opportunities exist for physician trainees to gain exposure to, and training in, the field of clinical informatics, an Accreditation Council for Graduate Medical Education-accredited, recently board-certified specialty. Currently, 21 approved programs exist nationwide for the formal training of fellows interested in pursuing careers in this discipline. Residents and fellows training in medical and surgical fields, however, have few avenues available to gain experience in clinical informatics. An early introduction to clinical informatics brings an opportunity to generate interest for future career trajectories. At University of California Los Angeles (UCLA) Health, we have developed a novel, successful, and sustainable program, the Resident Informaticist Program, with the goals of exposing physician trainees to the field of clinical informatics and its academic nature and providing opportunities to expand the clinical informatics workforce. Herein, we provide an overview of the development, implementation, and current state of the UCLA Health Resident Informaticist Program, with a blueprint for development of similar programs.

    View details for DOI 10.1093/jamia/ocw174

    View details for Web of Science ID 000405618200020

    View details for PubMedID 28115427

    View details for PubMedCentralID PMC7651961

  • Managing Scale and Innovation in Health IT JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Enzmann, D. R., Pfeffer, M. 2016; 13 (9): 1135-1138


    Given the high-intensity interaction between radiology and IT, radiology leadership should understand IT's new, somewhat conflicting, dual roles. Managing large-scale and small-scale projects concurrently has become an important challenge for leaders of health IT (HIT). Historical parallels of this challenge can be drawn from transportation and communication systems, in which a large-scale mind-set is needed to build the initial network, whereas a small-scale mind-set is more useful to develop the content that will traverse this network. Innovation and creativity is a cornerstone of content small-scale thinking, and in HIT, that is what is needed to extract the value from it. However, unlike the early historical transportation and communication examples, the time between the development of the infrastructure and the follow-on, value-rich content is shortened greatly because it has become nearly simultaneous in HIT. Weaving the ability to concomitantly manage both large- and small-scale projects into the fabric of the organizational HIT culture will be critical for its success.

    View details for DOI 10.1016/j.jacr.2016.02.024

    View details for Web of Science ID 000383313400027

    View details for PubMedID 27039000

  • A Systematic Approach to Creation of a Perioperative Data Warehouse ANESTHESIA AND ANALGESIA Hofer, I. S., Gabel, E., Pfeffer, M., Mahbouba, M., Mahajan, A. 2016; 122 (6): 1880-1884


    Extraction of data from the electronic medical record is becoming increasingly important for quality improvement initiatives such as the American Society of Anesthesiologists Perioperative Surgical Home. To meet this need, the authors have built a robust and scalable data mart based on their implementation of EPIC containing data from across the perioperative period. The data mart is structured in such a way so as to first simplify the overall EPIC reporting structure into a series of Base Tables and then create several Reporting Schemas each around a specific concept (operating room cases, obstetrics, hospital admission, etc.), which contain all of the data required for reporting on various metrics. This structure allows centralized definitions with simplified reporting by a large number of individuals who access only the Reporting Schemas. In creating the database, the authors were able to significantly reduce the number of required table identifiers from >10 to 3, as well as to correct errors in linkages affecting up to 18.4% of cases. In addition, the data mart greatly simplified the code required to extract data, making the data accessible to individuals who lacked a strong coding background. Overall, this infrastructure represents a scalable way to successfully report on perioperative EPIC data while standardizing the definitions and improving access for end users.

    View details for DOI 10.1213/ANE.0000000000001201

    View details for Web of Science ID 000376463000025

    View details for PubMedID 27195633

  • A Bad Case of Good's Syndrome INFECTIOUS DISEASES AND THERAPY Tachdjian, R., Keller, J. J., Pfeffer, M. 2014; 3 (2): 333-337


    Good's syndrome is a relatively rare immunodeficiency condition that presents in the fourth or fifth decade of life and is defined by hypogammaglobulinemia in the setting of a thymoma. The humoral defect may be severe enough to cause an absence in B cells, with a consequent recurrence of sinopulmonary disease, chronic non-infectious diarrhea and opportunistic infections. The prognosis in patients with Good's syndrome appears to be worse than in those with X-linked agammaglobulinemia (XLA) and common variable immune deficiency (CVID). There have only been three cases of Good's syndrome associated with mycobacterium, and only one case with a cavitary lesion in the lungs. We present here a unique case of Good's syndrome with a non-mycobacterial cavitary lesion.

    View details for DOI 10.1007/s40121-014-0045-7

    View details for Web of Science ID 000215319300021

    View details for PubMedID 25287948

  • Acute Aortic Dissection HOSPITAL MEDICINE CLINICS Pfeffer, M. A. 2012; 1 (1): E1-E11
  • Liquid crystal surface anchoring of mesophase pitch CARBON Jian, K. Q., Shim, H. S., Tuhus-Dubrow, D., Bernstein, S., Woodward, C., Pfeffer, M., Steingart, D., Gournay, T., Sachsmann, S., Crawford, G. P., Hurt, R. H. 2003; 41 (11): 2073-2083