Megan Vanneman is a postdoctoral fellow in health services research at the Center for Innovation to Implementation (Ci2i) in the VA Palo Alto Health Care System and at the Center for Health Policy/Primary Care and Outcomes Research (CHP/PCOR) in the Stanford University School of Medicine. Dr. Vanneman primarily studies the impact of policy change on access, quality, and cost in large healthcare systems, with a focus on vulnerable populations and mental health. She is currently studying the Veterans Choice Program, dual VA-Medicaid users, performance measurement, and post-deployment linkage to and engagement in health care at VA.

Professional Education

  • Bachelor of Arts, Stanford University, HUMBI-BA (2003)
  • Bachelor of Arts, Stanford University, SPAN-MIN (2003)
  • Master of Public Health, Columbia University (2005)
  • Doctor of Philosophy, University of California Berkeley (2013)

Stanford Advisors


All Publications

  • Are Improvements in Measured Performance Driven by Better Treatment or "Denominator Management"? Journal of general internal medicine Harris, A. H., Chen, C., Rubinsky, A. D., Hoggatt, K. J., Neuman, M., Vanneman, M. E. 2016; 31: 21-27


    Process measures of healthcare quality are usually formulated as the number of patients who receive evidence-based treatment (numerator) divided by the number of patients in the target population (denominator). When the systems being evaluated can influence which patients are included in the denominator, it is reasonable to wonder if improvements in measured quality are driven by expanding numerators or contracting denominators.In 2003, the US Department of Veteran Affairs (VA) based executive compensation in part on performance on a substance use disorder (SUD) continuity-of-care quality measure. The first goal of this study was to evaluate if implementing the measure in this way resulted in expected improvements in measured performance. The second goal was to examine if the proportion of patients with SUD who qualified for the denominator contracted after the quality measure was implemented, and to describe the facility-level variation in and correlates of denominator contraction or expansion.Using 40 quarters of data straddling the implementation of the performance measure, an interrupted time series design was used to evaluate changes in two outcomes.All veterans with an SUD diagnosis in all VA facilities from fiscal year 2000 to 2009.The two outcomes were 1) measured performance-patients retained/patients qualified and 2) denominator prevalence-patients qualified/patients with SUD program contact.Measured performance improved over time (P < 0.001). Notably, the proportion of patients with SUD program contact who qualified for the denominator decreased more rapidly after the measure was implemented (p = 0.02). Facilities with higher pre-implementation denominator prevalence had steeper declines in denominator prevalence after implementation (p < 0.001).These results should motivate the development of measures that are less vulnerable to denominator management, and also the exploration of "shadow measures" to monitor and reduce undesirable denominator management.

    View details for DOI 10.1007/s11606-015-3558-1

    View details for PubMedID 26951270

  • Army Active Duty Members' Linkage to Veterans Health Administration Services After Deployments to Iraq or Afghanistan and Following Separation MILITARY MEDICINE Vanneman, M. E., Harris, A. H., Chen, C., Mohr, B. A., Adams, R. S., Williams, T. V., Larson, M. J. 2015; 180 (10): 1052-1058


    This study described the rate and predictors of Operation Enduring Freedom/Operation Iraqi Freedom active duty Army members' enrollment in and use of Veterans Health Administration (VHA) services (linkage), as well as variation in linkage rates by VHA facility. We used a multivariate mixed effect regression model to predict linkage to VHA, and also calculated linkage rates in the catchment areas of each facility (n = 158). The sample included 151,122 active duty members who deployed to Iraq or Afghanistan and then separated from the Army between fiscal years 2008 and 2012. Approximately 48% of the active duty members separating utilized VHA as an enrollee within one year. There was significant variation in linkage rates by VHA facilities (31-72%). The most notable variables associated with greater linkage included probable serious injury during index deployment (odds ratio = 1.81), separation because of disability (odds ratio = 2.86), and various measures of receipt of VHA care before and after separation. Information about the individual characteristics that predict greater or lesser linkage to VHA services can be used to improve delivery of health care services at VHA as well as outreach efforts to active duty Army members.

    View details for DOI 10.7205/MILMED-D-14-00682

    View details for Web of Science ID 000364632900016

    View details for PubMedID 26444467

  • Linking the Legislative Process to the Consequences of Realigning California's Public Mental Health System ADMINISTRATION AND POLICY IN MENTAL HEALTH AND MENTAL HEALTH SERVICES RESEARCH Vanneman, M. E., Snowden, L. R. 2015; 42 (5): 593-605
  • Impact of participation in the California Healthcare-Associated Infection Prevention Initiative on adoption and implementation of evidence-based practices for patient safety and health care-associated infection rates in a cohort of acute care general hospitals AMERICAN JOURNAL OF INFECTION CONTROL Halpin, H. A., McMenamin, S. B., Simon, L. P., Jacobsen, D., Vanneman, M., Shortell, S., Milstein, A. 2013; 41 (4): 307-311


    In 2008, hospitals were selected to participate in the California Healthcare-Associated Infection Prevention Initiative (CHAIPI). This research evaluates the impact of CHAIPI on hospital adoption and implementation of evidence-based patient safety practices and reduction of health care-associated infection (HAI) rates.Statewide computer-assisted telephone surveys of California's general acute care hospitals were conducted in 2008 and 2010 (response rates, 80% and 76%, respectively). Difference-in-difference analyses were used to compare changes in process and HAI rate outcomes in CHAIPI hospitals (n = 34) and non-CHAIPI hospitals (n = 149) that responded to both waves of the survey.Compared with non-CHAIPI hospitals, CHAIPI hospitals demonstrated greater improvements between 2008 and 2010 in adoption (P = .021) and implementation (P = .012) of written evidence-based practices for overall patient safety and prevention of HAIs and in assessing their compliance (P = .033) with these practices. However, there were no significant differences in the changes in HAI rates between CHAIPI and non-CHAIPI hospitals over this time period.Participation in the CHAIPI collaborative was associated with significant improvements in evidence-based patient safety practices in hospitals. However, determining how evidence-based practices translate into changes in HAI rates may take more time. Our results suggest that all hospitals be offered the opportunity to participate in an active learning collaborative to improve patient safety.

    View details for DOI 10.1016/j.ajic.2012.04.322

    View details for Web of Science ID 000317416000005

  • Hospital adoption of automated surveillance technology and the implementation of infection prevention and control programs AMERICAN JOURNAL OF INFECTION CONTROL Halpin, H., Shortell, S. M., Milstein, A., Vanneman, M. 2011; 39 (4): 270-276


    This research analyzes the relationship between hospital use of automated surveillance technology (AST) for identification and control of hospital-acquired infections (HAI) and implementation of evidence-based infection control practices. Our hypothesis is that hospitals that use AST have made more progress implementing infection control practices than hospitals that rely on manual surveillance.A survey of all acute general care hospitals in California was conducted from October 2008 through January 2009. A structured computer-assisted telephone interview was conducted with the quality director of each hospital. The final sample includes 241 general acute care hospitals (response rate, 83%).Approximately one third (32.4%) of California's hospitals use AST for monitoring HAI. Adoption of AST is statistically significant and positively associated with the depth of implementation of evidence-based practices for methicillin-resistant Staphylococcus aureus and ventilator-associated pneumonia and adoption of contact precautions and surgical care infection practices. Use of AST is also statistically significantly associated with the breadth of hospital implementation of evidence-based practices across all 5 targeted HAI.Our findings suggest that hospitals using AST can achieve greater depth and breadth in implementing evidenced-based infection control practices.

    View details for DOI 10.1016/j.ajic.2010.10.037

    View details for Web of Science ID 000290019000004

    View details for PubMedID 21531272

  • Mandatory Public Reporting Of Hospital-Acquired Infection Rates: A Report From California HEALTH AFFAIRS Halpin, H. A., Milstein, A., Shortell, S. M., Vanneman, M., Rosenberg, J. 2011; 30 (4): 723-729


    One way to motivate hospitals to improve patient safety is to publicly report their rates of hospital-acquired infections, as California is starting to do this year. We conducted a baseline study of California's acute care hospitals just before mandatory reporting of hospital-acquired infection rates to the state began, in 2008. We found variability in many areas: For example, 70.1 percent of hospitals said that they were fully implementing evidence-based guidelines to fight infection by methicillin-resistant Staphylococcus aureus, but 22.8 percent of hospitals had not adopted any. Our analysis showed that rural hospitals, many of which lack resources to implement needed procedures, faced the greatest challenges in reporting and improving infection rates. Our findings should be of interest to Medicare policy makers who will implement the hospital-acquired infection performance measures in the Affordable Care Act, and to leaders in the thirty-eight states that have enacted legislation requiring reports of hospital-acquired infection rates. California's baseline data also present a unique opportunity to assess the impact of mandatory and public reporting laws.

    View details for DOI 10.1377/hlthaff.2009.0990

    View details for Web of Science ID 000289233400025

    View details for PubMedID 21471494

  • Patient safety climate: variation in perceptions by infection preventionists and quality directors. Interdisciplinary perspectives on infectious diseases Nelson, S., Stone, P. W., Jordan, S., Pogorzelska, M., Halpin, H., Vanneman, M., Larson, E. 2011; 2011: 357121-?


    Background. Healthcare-associated infections (HAIs) are an important patient safety issue, and safety climate is an important organizational factor. This study explores perceptions of infection preventionists (IPs) and quality directors (QDs) regarding two safety microclimates, Senior Management Engagement (SME) and Leadership on Patient Safety (LOPS), across California hospitals. Methods. This was an analysis of two cross-sectional surveys. We conducted Wilcoxon signed-rank test, univariate analyses, and a multivariate ordinary least square regression. Results. There were 322 eligible hospitals; 149 hospitals (46.3%) responded to both surveys. The IP response rate was 59%, and the QD response rate was 79.5%. We found IPs perceived SME more positively than did QDs (21.4 vs. 20.4, P < 0.01). No setting characteristics predicted variation in perceptions. Presence of an independent budget predicted more positive perceptions of microclimates across personnel types (P < 0.01). Conclusions. Differences in perceptions continue to exist between essential leaders in acute health care settings which could have critical effects on outcomes such as HAIs. Having an independent budget for the infection prevention and control department may enhance the overall safety climate and in turn patient care.

    View details for DOI 10.1155/2011/357121

    View details for PubMedID 21826140