Introduction
Disease surveillance systems and health data sources provide the raw information necessary to monitor trends in health and disease. Descriptive epidemiology provides a way of organizing and analyzing these data in order to understand variations in disease frequency geographically and over time, and how disease (or health) varies among people based on a host of personal characteristics (person, place, and time). This makes it possible to identify trends in health and disease and also provides a means of planning resources for populations. In addition, descriptive epidemiology is important for generating hypotheses (possible explanations) about the determinants of health and disease. By generating hypotheses, descriptive epidemiology also provides the starting point for analytic epidemiology, which formally tests associations between potential determinants and health or disease outcomes. Specific tasks of descriptive epidemiology are the following:
- Monitoring and reporting on the health status and health related behaviors in populations
- Identifying emerging health problems
- Alerting us to potential threats from bioterrorism
- Establishing public health priorities for a population
- Evaluating the effectiveness of intervention programs and
- Exploring potential associations between "risk factors" and health outcomes in order to generate hypotheses about the determinants of disease.
In this module we will provide you with the key elements of descriptive epidemiology and the descriptive statistics that are fundamental to defining the health status of populations, identifying health problems, and generating hypotheses about the determinants of health and disease.
Learning Objectives
After completing this this week's learning activities, you will be able to:
- Explain the role of descriptive epidemiology for defining health problems and establishing hypotheses about the determinants of health and disease
- Explain the utility and the limitations of case reports and case series
- Describe the design features and the advantages and weaknesses of each of the following study designs:
- Cross-sectional studies
- Ecological studies
- Explain the difference between a population parameter and a sample statistic.
- Distinguish among dichotomous, ordinal, categorical and continuous variable types
- Interpret appropriate numerical and graphical summaries for each variable type