Number of new cases per population at risk in a given time period is a definition of which of the following?

Incidence rate, also known as incidence, is a fundamental measure of disease frequency. It quantifies the number of new cases of a health outcome that develop in a population at risk during a specified period. The key components of this definition are the focus on new cases (distinguishing it from prevalence), the specific population at risk in the denominator (excluding those who already have the disease or are immune), and the defined time period over which these new cases are observed. This measure is crucial for understanding the risk of developing a disease and for studying disease etiology.

B. Prevalence rate measures the proportion of a population with a disease (both new and existing cases) at a specific point in time.

C. Mortality rate measures the frequency of death in a defined population during a specified interval.

D. Odds ratio is a measure of association that quantifies the odds of an outcome occurring in an exposed group compared to a non-exposed group.

E. Confidence Interval is a statistical range that estimates the precision of a point estimate, indicating where the true population parameter likely lies.

1. Centers for Disease Control and Prevention (CDC). (2012). Principles of Epidemiology in Public Health Practice

Third Edition. An Introduction to Applied Epidemiology and Biostatistics. Lesson 3: Measures of Risk

Section: Incidence Rate. Retrieved from https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section2.html

2. Gordis

L. (2014). Epidemiology (5th ed.). Elsevier Saunders. Chapter 3: Measuring the Occurrence of Disease: I. Morbidity

pp. 40-43. (This is a standard textbook in epidemiology used in numerous university public health programs).

3. Boston University School of Public Health. (n.d.). Measures of Disease Frequency. PH717 Module 2. Retrieved from https://sphweb.bumc.bu.edu/otlt/mph-modules/ep/ep713diseasefrequency/ep713diseasefrequencyprint.html (This university courseware explicitly defines incidence as "the number of new cases of a disease that develop in a population at risk over a specified time period.")