Concept Architecture
Concept
Theoretically, Case Fatality Rate (CFR) is an epidemiological measure that quantifies the proportion of individuals diagnosed with a specified disease who die from that disease during a defined period. It is an indicator of disease severity and clinical prognosis rather than disease transmission or population mortality. The concept is grounded in epidemiology and biostatistics and exists to compare the lethality of diseases, evaluate clinical management and assess healthcare system performance.
Mathematically, the Case Fatality Rate is represented as the ratio of deaths attributable to a specific disease to the total number of diagnosed cases of that disease, multiplied by 100 to express the result as a percentage. Because both the numerator and denominator relate only to confirmed cases, the measure estimates the probability of death among affected individuals rather than the risk within the general population.
In practice, Case Fatality Rates are calculated using surveillance systems, disease registries and clinical databases. They are widely used during infectious disease outbreaks, chronic disease monitoring and health technology assessments to estimate disease burden, model survival outcomes and inform cost-effectiveness analyses involving mortality-related health outcomes.
Purpose
Used to quantify disease severity, evaluate clinical outcomes, compare healthcare performance, estimate disease burden and inform epidemiological and health economic analyses.
Mathematical Formulae
Primary Formula
Case Fatality Rate = (Number of Deaths from the Disease � Number of Confirmed Cases) ? 100
Supporting Formulae
Case Fatality Ratio = Deaths � Confirmed Cases
Survival Proportion = 1 ? (Deaths � Confirmed Cases)
Related Mathematical Methods
- Incidence proportion
- Mortality rate
- Survival analysis
- Kaplan-Meier estimation
- Hazard ratio estimation
- Logistic regression
Example
An outbreak results in 2,500 confirmed cases of a disease, of which 125 patients die.
Case Fatality Rate = (125 � 2,500) ? 100
= 5%
The disease therefore has a Case Fatality Rate of 5%, indicating that approximately five out of every 100 confirmed cases resulted in death during the reporting period.
Excel Implementation
| Function | Example Formula | Health Economics Application |
|---|---|---|
| COUNTIF | =COUNTIF(B2:B2501,"Death") | Count disease-related deaths. |
| COUNTA | =COUNTA(A2:A2501) | Count confirmed disease cases. |
| COUNTIF/COUNTA | =(COUNTIF(B2:B2501,"Death")/COUNTA(A2:A2501))*100 | Calculate the Case Fatality Rate. |
| AVERAGE | =AVERAGE(C2:C13) | Calculate the average monthly Case Fatality Rate. |
| IF | =IF(D2>5,"High Fatality","Expected Range") | Compare observed Case Fatality Rates with historical benchmarks. |
VBA (Optional)
Automate calculation of Case Fatality Rates by disease, age group, healthcare facility and reporting period while generating epidemiological surveillance dashboards.
Sources
- Porta M, editor. A Dictionary of Epidemiology. Oxford University Press.
- Rothman KJ, Greenland S, Lash TL. Modern Epidemiology.
- Gordis L. Epidemiology.
- World Health Organization. Principles of Epidemiology and Public Health Surveillance.
- Drummond MF, Sculpher MJ, Claxton K, Stoddart GL, Torrance GW. Methods for the Economic Evaluation of Health Care Programmes.
- Briggs A, Claxton K, Sculpher M. Decision Modelling for Health Economic Evaluation.
Related Concepts (2)
Library
Publications
1
Health at a Glance 2023: OECD Indicators — Organisation for Economic Co-operation and Development, 2023 Edition ed., 2023 (OECD Publishing)
OECD’s comprehensive biennial compendium of comparative indicators on population health and health-system performance across member and partner countries — health status, risk factors, access, quality, resources and spending — the standard cross-country benchmarking reference.
Frequently Asked Questions (6)
What is the case fatality rate?
The proportion of people diagnosed with a disease who die from it within a defined period, a measure of disease severity.
Source: Rothman KJ, Greenland S, Lash TL. Modern Epidemiology. 3rd ed. Lippincott Williams & Wilkins; 2008.
What proportion of the diagnosed does the case fatality rate express?
The case fatality rate expresses the proportion of people diagnosed with a disease who die from it within a defined period. It is the share of those who have the disease that the disease kills, a ratio of deaths to diagnosed cases. It measures the severity of a disease, showing how deadly it is for those who contract it. It applies over a defined period, the window within which deaths are counted. It differs from the mortality rate, which measures deaths across a whole population rather than only among those diagnosed. How deadly a disease is for its sufferers is what it expresses. Rothman, Greenland and Lash (2008) set this out.
Source: Rothman, Greenland & Lash 2008
What proportion does the case fatality rate express?
The case fatality rate expresses the proportion of people diagnosed with a disease who die from it within a defined period, so it is the share of diagnosed people who die of the disease over that period. This proportion of the diagnosed defines it. So the case fatality rate is the proportion of people diagnosed with a disease who die from it within a defined period, a measure of disease severity.
Source: Rothman, Greenland & Lash 2008
What does the case fatality rate measure?
The case fatality rate measures disease severity, so the proportion of people diagnosed with a disease who die from it within a defined period serves as a gauge of how severe the disease is. This measurement of severity defines its purpose. So the case fatality rate is the proportion of people diagnosed with a disease who die from it within a defined period, a measure of disease severity.
Source: Rothman, Greenland & Lash 2008
Over what does the case fatality rate apply?
The case fatality rate applies within a defined period, so it is the proportion of people diagnosed with a disease who die from it over that specified period. This defined period defines its timeframe. So the case fatality rate is the proportion of people diagnosed with a disease who die from it within a defined period, a measure of disease severity This difference in denominator is what separates the case fatality rate from the mortality rate as measures of death.
Source: Rothman, Greenland & Lash 2008
How does the case fatality rate relate to the mortality rate?
The case fatality rate relates to the mortality rate in that both concern death but over different denominators: the case fatality rate is the proportion of people diagnosed with a disease who die from it, while the mortality rate is death frequency within a defined population over a period. So the case fatality rate is deaths among the diagnosed and the mortality rate is deaths in the population, connected as measures of death with different reference groups.
Source: Rothman, Greenland & Lash 2008
Trust Record
Verified by Dr Darrin Baines
British health economist
Professional identity: darrinbaines.org
Verification date: 10 Mar 2026
Content version: 1.0.0
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- Term code
- HS-HP-PHO-002
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