OLR Research Report

September 18, 2008




By: Saul Spigel, Chief Analyst


“Evidence-based medicine (EBM)” is an increasingly popular concept among state health care policymakers who see it as a tool for improving health care and saving money. Connecticut legislators have, for example, required the Social Services Department (DSS) to establish a child health quality improvement program to promote the use of “evidence-based strategies” among HUSKY providers (CGS 17b-306a). And recent bills here have called for (1) state health agencies to incorporate recommendations from organizations promoting evidence-based research into their long-range planning (HB 5038 (2008)) and (2) the development of a strategic plan for chronic disease management that uses evidence-based clinical practice guidelines (HB 6976 (2007)).

This report looks at what EBM is; who determines when medicine is evidence-based; how these decisions are translated into medical practice and health policy; obstacles health care providers and state policymakers face in applying using EBM; and how states currently use EBM.


Evidence-based medicine is commonly defined as “the conscientious, explicit, judicious, use of best current evidence in making decisions about the care of individual patients.” Practicing EBM means integrating the best available external clinical evidence from systematic research with individual clinical expertise.

This definition reflects the EBM movement's early focus on developing research-based practice guidelines that individual health care providers could use in treating individual patients. Recently, the use of EBM has spread to public and private insurance coverage, benefit design, and medical necessity decisions; performance measurements and payments; and other policy decisions.

EBM involves the expert analysis of clinical evidence from well-designed and well-executed studies. Large, double-blind, randomized controlled trials and, particularly, “meta-reviews” of such trials (statistical analysis of multiple trials) are the “gold standard” of EBM. When these are lacking, analysts rely on other methods like small randomized trials (which have less statistical validity), studies without a random control group, case studies, and other observations. This research typically examines the efficacy (how well an intervention works under ideal conditions) and safety of new treatments and the processes health care providers should use in best caring for patients. Using anesthesia during cataract surgery, pharmacologic treatment of dementia, and islet transplants in patients with type I diabetes are examples of typical EBM studies.

As the use of EBM broadens from clinical practice to public policy decisions, analysts also look at whether the evidence on which a practice is based applies to populations beyond those initially studied, a practice's effectiveness compared to other treatments, patient outcomes, and cost-benefit. Examples of EBM in the policy area are the effectiveness of continuing medical education, training clinicians in bioterrorism preparedness, and care coordination strategies for children with special health care needs.


Many groups in the U.S. and elsewhere determine when the scientific evidence is sufficient to use in making clinical and policy decisions. Their determinations typically come in the form of practice guidelines. The following are among the more prominent groups.

● The Agency for Healthcare Research and Quality (AHRQ), a branch of the U.S. Health and Human Services Department, is the principal U.S. entity supporting EBM. It funds 14 evidence-based practice centers (EPCs) in the U.S. and Canada. Four of the centers focus on technology assessments for the Center for Medicaid and Medicare Services; one focuses on preventive services; and the others (including UConn as of 2007) study topics nominated by other federal agencies, professional societies, health systems, employers, insurers, providers, and consumer groups.

● AHRQ also funds two other specialized evidence-based research programs. The outcomes and effectiveness program studies how EBM practices affect patient outcomes. The U.S. Preventive Services Task Force, an independent panel of primary care and prevention experts, systematically reviews evidence of effectiveness and develops recommendations for clinical preventive services.

● The National Institute of Health and Clinical Excellence (NICE) is the independent organization responsible for providing guidance to the British National Health Service and private practitioners on promoting good health and preventing and treating illness. NICE produces guidance in three areas: public health (health promotion and prevention), health technologies (drugs, treatments, and procedures), and clinical practice. In addition, it offers clinicians advice on how to implement its guidance, tools on estimating implementation costs, and other educational tools.

● The Cochrane Library is the world's largest electronic collection of systematic reviews of medical studies. The reviews are written by members of the Cochrane Collaboration, a private, international organization with more than 12,000 members from 91 nations. The library contains over 1,000 clinical practice guidelines and a health economic evaluations database that contains studies of cost-effectiveness and other forms of economic evaluation of medicines, other treatments, and medical interventions. Access to the library is available only by subscription.

● The Drug Effectiveness Review Project (DERP) is a consortium of 14 states and a Canadian province that commissions evidence-based reviews of the comparative effectiveness and safety of drugs in many widely used drug classes. Its members use this information to make drug coverage and other policy decisions. The Oregon Health and Science University (an AHRQ EPC) Center for Evidence-Based Policy conducts the reviews (along with another EPC at the University of North Carolina) and oversees the project.

The American Academy of Pediatrics, American Academy of Family Physicians, American College of Cardiologists are among various medical organizations that write evidence-based practice guidelines for their particular specialties.

(Internet links to many of these organizations are found at the end of this report.)


The organizations described above and others have written and compiled thousands of research-based clinical practice and other guidelines. Providers and policy makers can obtain these guidelines from many sources. These include (1) the Internet, (2) medical journals, (3) medical school and continuing medical education curricula, (4) practice reminders from insurers or physician networks, and (5) computerized decision-support systems.

The Internet provides numerous EBM resources. The Cochrane Library is the largest Internet collection of guidelines, but it is available only by subscription. AHRQ maintains the National Guidelines and Quality Measures Clearinghouses, which offer various databases containing detailed information on practice guidelines and quality measures. AHRQ also maintains an “effective health care” website that provides short, comprehensive summaries of research reviews geared to consumers, clinicians, and policymakers and the complete text of those reviews. And the federal Substance Abuse and Mental Health Services Administration (SAMHSA) maintains a National Registry of Evidence-Based Programs and Practices. Its website also connects clinicians to third party websites that contain intervention and treatment guidelines. 

Since 2000, AHRQ has funded over 25 “translating research into practice” projects that use rigorous studies to learn what strategies work best in implementing EBM in different contexts. The projects focuses on using information technology as tool for translating research into practice. AHRQ is currently working with academic health centers (including UConn), managed care organizations, and physician practice networks to more rapidly disseminate research findings.


Health Care Practitioners

Translating EBM into sustainable improvements in clinical care and patient outcomes is difficult, according to AHRQ. It can take up to 20 years, it says, before research findings become part of routine clinical practice. One study of physicians' use of guidelines for pertussis vaccinations found 90% were aware of the guidelines, 67% agreed with them, 46% adopted them, but just 35% adhered to them.

Several individual and institutional obstacles along the path from research to treatment help explain these gaps. The former include: (1) lack of awareness or acceptance of a relevant guideline, (2) failure to understand a guideline's applicability to a particular patient, (3) lack of training in applying a guideline, (4) lack of a pressing treatment focus (omissions occur most often in applying preventive care guidelines), and (5) patients not agreeing or failing to follow a guideline.

Health care professionals work in organizations that can pose institutional obstacles to implementing EBM. These obstacles include: (1) opposing external forces (e.g., drug company marketing or peers); (2) how the care process is organized; (3) available time, staff, and resources; (4) organizational management and policy; and (5) lack of financial compensation. EBM use is more likely to occur in patient care settings, like hospitals and clinics, where providers work closely together than it is in solo or small practices.


Legislators and administrative policymakers also face personal and institutional barriers when trying to apply EBM to health care policy decisions. The most significant personal barrier is their lack of training or experience in assessing scientific research, understanding the function of systematic reviews, and applying EBM to policy decisions. These deficits make it difficult for them to assess evidence submitted to them as research-based in either support or opposition to a proposed policy. As a result, officials are often unable to distinguish between good and bad data.

The legislative process itself poses obstacles to using evidence in making health care policy. Because legislators must make many decisions in a very short time frame, they are overwhelmed with information and have only limited ability to accumulate much information about any one issue. Most tend to compartmentalize expertise and rely on others—other legislators, the executive branch, and groups with vested interests—for information on issues outside those knowledge areas.

Proposed health care legislation is often based on little or no scientific evidence; it arises from a single event, a constituent's anecdote, or an interest group's claims. Even when valid scientific evidence is presented, it often fails to come in a form legislators can use. It is written for experts and is difficult for nonexperts to interpret, typically does not address health outcomes or economic effects, and usually does not convey the emotional power of personal experience (Jewell and Bero,

“Developing Good Taste in Evidence”: Facilitators of and Hindrances to Evidence-Informed Policymaking in State Government, Milbank Quarterly, 2008,


Although they face the barriers described above, policymakers in several states have begun to apply EBM in some policy decisions. These include designing public insurance benefit packages and reviewing mandated benefits, developing preferred drug lists, determining health care provider payments, and making certificate of need decisions. Minnesota, Oregon, and Washington appear to be in the forefront of using EBM.

Benefit Design

Using research-based evidence to design insurance benefits can help achieve cost-effective care in two ways: (1) decreasing the use of more expensive treatment options, especially those without greater proven effectiveness and (2) encouraging—or at least not discouraging—the use of services known to be clinically effective.

Oregon. The legislature created a Health Fund Board to develop a comprehensive plan to ensure access to health care, contain health care costs, and address health care quality issues. The board must submit the plan to the legislature in January 2009. Its draft plan calls for establishing an “essential benefits package” that would constitute a minimum level for all public and private insurance. It calls for little or no cost sharing for evidence-based preventive care that is shown to keep individuals with chronic illnesses from experiencing preventable acute exacerbations of their disease.

The draft also calls for:

1. a public-private collaborative effort to (a) implement common clinical coverage guidelines and standards and (b) promote and expand comparative effectiveness research in order to reduce variations in medical care among Oregon communities and help control costs in treating chronic conditions;

2. a clinical improvement assessment project in which public purchasers of health care (i.e., Medicaid, State Children's Health Insurance Program, public employees, and corrections) conduct and support research on the comparative outcomes, clinical effectiveness, and appropriateness of pharmaceuticals, devices, and services; and

3. state support for providers to adopt technology that supports EBM and clinical decision making.

The Oregon plan cites the work of Minnesota's Institute for Clinical System Improvement (ICSI). ICSI is an independent, nonprofit organization that facilitates collaboration on health care quality improvement by medical groups, hospitals, and health plans that provide health care services to state residents. The group produces evidence-based best practice guidelines, protocols, and order sets that are recognized as the standard of care in Minnesota. In addition, it facilitates collaborations between medical groups and hospitals to share best practices and strategies to accelerate their quality improvement work.

Washington. In 2006, the legislature established an independent Health Technology Assessment Committee to determine (1) which health technologies various state health programs will cover and any conditions that might apply to coverage and (2) criteria the administering agencies must use to decide whether the technology is medically necessary or proper and necessary treatment. Under this law, health technology means medical and surgical devices and procedures, medical equipment, and diagnostic tests.

The committee reviews up to eight technologies a year selected by the state's health care authority director. Selections are based on high state spending for the technology or concerns about its safety, efficacy, or cost-effectiveness. In making its determinations, the committee must review a systematic assessment of the evidence of the technology's safety, efficacy, and cost-effectiveness conducted by an EPC or similar entity. State agencies can pay for unreviewed technologies under their existing authority to make coverage decisions (RCW 70.14.080 to 120).

Colorado. In a more limited use of EBM to design benefits, a 2006 Colorado law allows small employer insurance carriers to offer a high-deductible, EBM-derived benefit plan that can exclude certain otherwise mandated coverages. The plan must cover limited prevention and screening based on the latest medical evidence, limited elective inpatient and surgical care, limited medications, and maternity care (SB 36).

Benefit Review

A 2004 study found that 12 of the 26 states that require reviews of their health insurance mandates use medical efficacy as a review criterion (Bellows, et. al., “State Mandated Benefit Reviews,” Health Services Research, 41:3, part II (June 2006)). California's law, for example, establishes a program at the University of California to review legislative proposals to add or repeal health insurance mandates. The law requires the program to assess a proposal's medical, social, and financial effects. In assessing the medical effects, the program must examine the extent to which the medical community recognizes the benefit or service under consideration as being effective in screening, diagnosing, or treating a condition or disease. This effectiveness must be demonstrated by a review of scientific and peer-reviewed medical literature (CA Health & Safety Code 127660).

In practice, program staff conducts systematic reviews of the medical literature to assess the proposed mandate's efficacy and effectiveness for California residents. The scope of review is broad. Staff looks at the entire gamut of medical care the proposal entails—screenings, treatments, and resulting health outcomes for the varied populations it might affect. The program has recently reported on coverage mandates for (1) amino acid–based elemental formulas for people with certain gastrointestinal tract conditions, (2) durable medical equipment, and (3) screening and diagnostic tests of breast conditions.

Prescription Drug Coverage

Many states require their Medicaid programs to use a preferred drug list (PDL). Oregon law, for example, requires the Human Services Department to maintain a drug list that gives its Medicaid enrollees access to the most effective prescription drugs for their clinical conditions at the best possible price. It also requires the department to use evidence-based evaluations in developing a PDL for the state program that subsidizes drug purchases for seniors and state and local agencies' employees (ORS 414. 316 & 334).

An independent council of Oregon health practitioners develops the Medicaid list. It uses DERP (see “Who Determines” section, above) to obtain the latest peer-reviewed research of therapeutic drug classes, including products' comparative effectiveness. The council does not consider a drug's price. After the council completes the clinical review process and makes its recommendations on effectiveness, the Human Services Department adds price consideration in making its PDL decisions.

Similarly, Washington's Health Care Authority contracts with DERP to conduct evidence-based reviews of various classes of drugs' safety, efficacy, and effectiveness. A Pharmacy and Therapeutics Committee evaluates the reviews and makes recommendations to the authority and

the Social and Health Services and Labor and Industries departments, which then jointly perform a cost analysis and decide which drugs to add to the state's PDL (RCW 70.14.050).

Connecticut also maintains a PDL for its Medicaid and State-Administered General Assistance programs and has established a Pharmaceutical and Therapeutics Committee to review and evaluate medical standards and criteria for inclusion of drugs on the list (CGS 17b-274d). DSS contracts with Provider Synergies, a company that manages PDLs and negotiates supplemental rebates for Medicaid agencies in several states, to conduct the drug reviews and evaluations.

Provider Compensation

Many states, the federal government, and insurers are exploring ways to change how they pay health care providers from a system based on the number or type of patient encounters to one based on patient outcomes or other quality measurements. As Minnesota shows, EBM could be a part of such a “pay for performance” system.

The Minnesota legislature created a 13-member Health Care Transformation Task Force to develop a plan to improve the health status of Minnesotans and their access to affordable, quality health care. The task force's 2008 report was the basis for legislation that included provisions for evidence-based incentive payments for health care providers.

The new law calls for the health commissioner to develop a standardized set of measures for assessing health care quality. These measures must be based on medical evidence; give priority to outcome, rather than process, measures; and incorporate primary care measures such as preventive services, coronary artery and heart disease, diabetes, asthma, and depression. The commissioner must also develop a system for adjusting these measures to account for patient risk levels and for measuring health outcomes.

Beginning July 1, 2009, the commissioner must develop a system of quality incentive payments linked to targets based on and consistent with these quality measures. The payments are in addition to existing payment levels. They must, to the extent possible, adjust for variations in patient population in order not to give providers an incentive to avoid high-risk patients.

The law requires the state to begin using the incentive payment system in its state group health insurance system by July 1, 2010. And all health plans must begin using the standardized quality measures by January 1, 2010 (Minn. Session Law 2008, ch. 358).

Certificate of Need

About 36 states, including Connecticut, require some form of state review before a health care facility can introduce a new service or terminate an existing one. Some of these certificate of need (CON) reviews incorporate EBM.

Vermont's CON law, for example, requires applicants to show that a proposed project is consistent with the state's health resource allocation plan, which contains specific CON standards. These standards call for the proposal to foster certain goals and values including: (1) increasing the number of people who receive care that is consistent with evidence-based standards; (2) promoting clinical care that is consistent with scientific evidence; (3) embedding evidence-based guidelines into daily clinical practice; and (4) using evidence from peer-reviewed journals or controlled studies that permits definitive conclusions about the effectiveness, safety, and efficiency of high-technology services new to the state.

Maine's CON procedures also require projects to be consistent with the state health plan, which sets priorities for projects. Projects that protect health and safety have the highest plan priority. These include projects that, among other characteristics, show evidence-based strategies to reduce the impact of such chronic illness as cardiovascular disease, cancer, asthma, chronic lung disease, diabetes, and mental illness. Projects that advance access to services and reflect an evidence-based strategy for introducing new services and technologies are the third priority in the plan. Applicants for such projects must provide evidence showing detailed analysis of peer-reviewed research and data supporting the technology. The Maine Quality Forum, an independent entity established by the legislature to advocate for quality health care, must recommend projects.

Promoting EBM Among Providers

In addition to adopting EBM at the state level, some states promote its use at the local level. Connecticut's Department of Mental Health and Addiction Services (DMHAS), for example, has adopted a goal to promote evidence-based practice and has introduced several initiatives to this end. Its Education and Training Division trains and provides technical assistance to contracted substance abuse treatment provider agencies on evidence-based practices such as motivational enhancement/cognitive behavioral therapy. Its youth suicide prevention initiative is helping several school systems introduce a suicide prevention curriculum that is listed on SAMHSA's National Registry. And DMHAS is developing an internal capacity for monitoring providers' use of evidence-based practices.


The January/February 2005 issue of Health Affairs contains several articles on EBM. They can be viewed at

AHQR maintains several sites dedicated to EBM:

● Its evidence-based practice website ( provides an overview of the program and links to the reports it sponsored and the outcomes and effectiveness and effective health care sites.

● The National Guideline Clearinghouse is at

● The National Quality Measures Clearinghouse is at (

SAMHSA also maintains several EBM-related websites:

● Its Web Guide to EBPs is at

● The National Registry of Evidence-Based Programs and Practices at

More information on the Cochrane Collaboration is at

More information on Britain's National Institute of Health and Clinical Excellence is at

For more information on the Drug Effectiveness Review Project, go to

Details on Oregon's Health Fund Board and its recommendations for comprehensive reform are at

More on the California Health Benefits Review Program is at