What separates the case-fatality rate from the death-to-case ratio?

1. Both measures put deaths over cases, so the difference lies in which deaths are allowed into the numerator. 2. In the case-fatality rate the deaths must be deaths of the very cases counted in the denominator, which makes it a proportion. 3. In the death-to-case ratio the deaths need only fall in the same period, so many can belong to people who fell ill years earlier. 4. Neither measure is tied to a one year window, and the periods for numerator and denominator of a case-fatality rate need not even match. 5. Live births belong to infant and maternal mortality measures, never to case-fatality. 6. Which of the two comes out larger depends on the disease, so no ordering holds in general. _Source: CDC Principles of Epidemiology in Public Health Practice (3rd ed., US federal, public domain), Lesson 3 "Measures of Risk", section Case-fatality rate_