Cost-Effectiveness Analysis

What to know

  • Examines intervention's cost and health outcomes
  • Intervention cost - averted medical/productivity cost = Net cost
  • Positive net cost interventions are reported as a cost-effectiveness ratio
  • Negative net cost interventions are reported as net cost savings
balance beam with money on one side and medical heart on another icon

What is cost-effectiveness analysis?

Cost-effectiveness analysis (CEA) is a way to examine both the costs and health outcomes of one or more interventions. It compares an intervention to another intervention (or the status quo) by estimating how much it costs to gain a unit of a health outcome, like a life year gained or a death prevented.

Keep in mind‎

Because CEA is comparative, an intervention can only be considered cost effective compared to something else.

What inputs are included?

  • Net cost is the intervention costs minus averted medical and productivity costs.
  • Changes in health outcomes are outcomes with the intervention in place minus outcomes without the intervention in place.
  • Examples of health outcomes include heart attacks and deaths from heart disease.

What output does a cost-effectiveness analysis provide?

CEA provides information on health and cost impacts of an intervention compared to an alternative intervention (or the status quo). If the net costs of an intervention are positive (which means a more effective intervention is more costly), the results are presented as a cost-effectiveness ratio. A cost-effectiveness ratio is the net cost divided by changes in health outcomes. Examples include cost per case of disease prevented or cost per death averted. However, if the net costs are negative (which means a more effective intervention is less costly), the results are reported as net cost savings.

Intervention is More Effective and More Costly Example

The example below presents the results from a cost-effectiveness analysis of a screening intervention for preventing chlamydia infections among high risk women (compared to the status quo of no screening). The results are presented as a cost-effectiveness ratio. This cost-effectiveness ratio can be compared to another intervention to determine which is more cost-effective.

Sexually Transmitted Diseases

This analysis modeled the intervention as applied to 10000 women

Calculate Net Cost
Costs of implementation (cost of testing and treatment):

Cost averted (cost of treating pelvic inflammatory disease (PID):

Net costs (positive value means money spent):
$23,844



$13,033


$10,811

Identify change in health outcomes:
In this case,
10.6 PID cases averted
Calculate cost-effectiveness ratio:

Net costs/Change in health outcome = $10,811/10.6 =



$1020 per PID case averted

Intervention is More Effective and Less Costly Example

In the example below, we compare the childhood vaccination program to the status quo of no vaccination program. We can see that the costs of implementing the program are less than the medical and productivity costs averted. Because the intervention is cost saving, the results are not presented as a cost-effectiveness ratio. Instead, they are presented as net cost savings.

Childhood Vaccination Program

Costs of implementation:
$ 7.5 billion
Cost averted (medical costs & productivity losses):
-$76.4 billion
Net costs (negative value means cost savings):
-$68.9 billion

For additional information, please see the example as used in the CDC Introduction to Economic Evaluation in Public Health online training, as well as the original study.

How can information from a CEA be useful for decision makers?

CEA can be useful in comparing the health and cost impacts of different interventions affecting the same health outcome. It can also be useful for understanding how much an intervention may cost (per unit of health gained) compared to an alternative intervention. For example, a decision maker might find it useful to know if an intervention is cost saving, and if not how much more would it cost to implement it compared to a less effective intervention.

Resources

CDC Introduction to Economic Evaluation - Course providing a broad overview of economic evaluation methods with illustrative examples from public health

Tufts Medical Center Cost-Effectiveness Analysis Registry - Comprehensive database of cost-effectiveness analyses on a wide variety of diseases and treatment