About the Evidence Summaries

The Initiative

The 6|18 Initiative aims to help public health professionals, insurers, healthcare providers, and employers use evidence-based interventions identified by CDC to improve health and control healthcare costs.

How CDC Determined 6|18’s Conditions and Interventions

CDC’s policy specialists gathered CDC subject-matter experts to identify health conditions that:

  • Affect large numbers of people.
  • Are related to high healthcare costs.
  • Have proven interventions that could improve health and reduce healthcare costs.

We consulted experts in insurance, healthcare, and health administration to identify interventions for improving health and controlling costs. Additionally, we asked what kind of evidence they consider when selecting new services.

Our consultation with experts and our own evidence review framework (described below) resulted in evidence summaries for each of the 6|18 health conditions. These evidence summaries identify the 6|18 interventions and highlight studies that show opportunities to improve health and reduce healthcare costs.

Frameworks Used to Create the Evidence Summaries

In addition to expert opinion, CDC consulted two frameworks to help develop the evidence summaries:

CDC Conceptual Framework

We reviewed and adapted the CDC Conceptual Frameworkexternal icon to determine which levels of evidence to consider in our review. Based on feedback from healthcare insurance experts, we modified inclusion criteria to include only studies with significantly sized case numbers. We also considered five topic areas from the CDC Conceptual Framework to structure our evidence review:

  • Effectiveness – How well did the intervention achieve the desired outcome?
  • Reach – How well did the intervention reach the target group of people?
  • Feasibility – How well can the intervention be put into practice?
  • Sustainability – What will it take to maintain the intervention over time?
  • Transferability to other settings – What other settings have used the intervention successfully?

The Policy Analytical Framework

Before developing evidence reviews, we consulted the Policy Analytical Frameworkpdf icon since some of the proposed interventions might be used to inform policy recommendations for healthcare providers, insurers, and employers.

The Policy Analytical Framework includes economic considerations and provides a method to consider policies that can improve health. Based on healthcare professionals’ feedback and what insurers consider when making decisions, we included and modified three criteria from the Policy Analytical Framework:

  • Public Health Impact
  • Feasibility
  • Economic and Budgetary Impact

6|18 Evidence Summary Criteria

By consulting with internal and external experts and reviewing two CDC frameworks, we developed our criteria evidence and used it to review studies for the 6|18 Initiative. We drew from electronic databases containing reviews (systematic reviews or synthesis of data from multiple studies) and individual studies. We gathered literature from CDC experts, health and medical databases, and sources like The Guide to Community Preventive Services (the Community Guide), the United States Preventive Services Task Force (USPSTF), and the Agency for Healthcare Research and Quality.

To be included in the evidence summaries, an item had to meet a moderate, strong, or rigorous level of evidence.

Level of Evidence

Definitions and Examples

Level of Evidence


Definitions and Examples

  • Non-peer-reviewed evaluations of intervention;
  • Publications that show evidence of impact (e.g., large case studies with appropriate evaluation, evaluation reports from expert bodies)

Level of Evidence


Definitions and Examples

  • Case-control or cohort analytic studies;
  • Peer-reviewed journal publications;
  • Published reports from consensus panels such as the Advisory Committee on Immunization Practices;
  • Published peer-review evaluations of a single intervention with evidence of impact

Level of Evidence


Definitions and Examples

  • Evaluations of interventions or studies with systematic review that have evidence of impact (e.g., meta-analyses, The Community Guide)

We used a table modified from the CDC Policy Analytical Framework to review materials with policy and economic information:


Example Review Question


Public Health Impact

Example Review Question

What population will benefit? How much? When? Are the populations in the study group similar to the payer’s target population?



Example Review Question

What is the chance that decision makers can successfully implement the proposed policy?


Economic and Budgetary Impact

Example Review Question

What are the budgetary costs and benefits associated with the policy?
How do costs compare with benefits (e.g., cost-savings, costs averted, return on investments, cost-effectiveness, cost-benefit analysis)—especially in the short (1–3 year) term?

Could the payer or purchaser’s employees or enrolled persons lose less time from work as a result of this intervention?

This process resulted in a summary of evidence for the six conditions’ proposed interventions.

Evidence Summary Format

Each of the evidence summaries highlight one or more evidence-based interventions. These interventions give healthcare providers, payers, and employers possible interventions for their populations.

Each evidence summary includes:

  • Fast Facts – Who is at risk? How does this condition harm health?
  • Evidence-Based Interventions
  • What You Can Do
  • Selected Studies Behind the Interventions
  • Resources

Selected Studies Behind the Interventions highlights studies, systematic reviews, and health and cost impact information about the interventions.