Because epidemiology is a study between people, researchers can't or can't fully grasp or control the conditions under which the subjects occur. Therefore, observation is a very important method.
1. descriptive study, also known as descriptive epidemiology, accurately and in detail records the distribution characteristics of diseases or health conditions according to time, place and population characteristics (such as age, gender, occupation and nationality). Through observation, it may also include the distribution characteristics of suspected etiology. In order to describe the distribution correctly, there must be clear and unified diagnostic criteria, accurate number of cases (or factors) and population.
The data obtained by describing epidemiology can also provide clues or hypotheses for the etiology of diseases, or put forward effective prevention and control measures.
2. analytical study Analytical study, also known as Analytical epidemiology, further explores the conditions and laws of disease occurrence in the selected population according to the assumed causes or epidemic factors, and verifies the proposed assumptions. There are mainly two kinds: ① The method of finding the cause (cause) from the disease (result) is called case-control study, which is retrospective in time, so it is also called retrospective study. ② The research method of observing whether the result (disease) occurs from whether there are suspicious causes (etiology) is called cohort study. It is prospective in time, so it is also called prospective research.
Many other related technologies and methods need to be widely used in epidemiological research. The number of methods required exceeds the clinical needs. For example, typhoid fever can be diagnosed by clinical culture, and epidemiology sometimes needs to know its phage type or other characteristics; Only bacteria need to be isolated from patients clinically, and bacteria in foreign objects, soil and water should also be examined in epidemiology. Epidemiology needs to be tested by a large number of people, and a rapid method is needed to test a large number of specimens in a short time. Therefore, epidemiological research needs a variety of well-equipped experiments to serve it.
(2) experimental methods
The experimental method used in epidemiology is also called experimental epidemiology, which is different from the experiments of general basic medical disciplines and is mainly carried out in the field of population. The crowd scene is the main and largest laboratory of epidemiology. According to different research objects, it can be divided into clinical trials and community field trials. In the latter type of experiment, intervention research is also called intervention research. When the observed objects cannot be randomly grouped, it is called quasi-experimental research, such as feasibility study of health policy, evaluation study of management and service, etc.
(3) Research on theory and method.
1. Theoretical epidemiological research, also known as mathematical epidemiological research, is to establish relevant mathematical models or computer simulations for theoretical research based on the data obtained from epidemiological investigation, also known as mathematical theoretical research.
2. Methods Before starting a specific study, it is necessary to improve the technology used in the study, develop the technology of collecting data, and improve the classification of diseases. It is necessary to carry out and improve epidemiological research, but it is not a direct epidemiological study.