Laws & Regulations
A state bans the sale of a food that is considered unhealthy leading to a dramatic decline in its consumption. Other states in the same country continue to sell the food item and resemble a control group.Accidents
A train accident spills a petrochemical into a lake. Nearby lakes are unaffected and resemble a control. This situation may be used to model the effect of pollutants on ecosystems and organisms.Families
Family situations such as identical twins separated at a young age. This may be compared to identical twins who grew up together.Habits
Habits such as heavy smokers, moderate smokers, occasional smokers and nonsmokers who live in the same area and have similar living conditions with the exception of their tobacco exposure. Here tobacco usage can be viewed as an independent variable and health outcomes as dependent variables. Habits often don't exhibit random assignment. For example, heavy smokers may have things in common such as stress or a poor diet that impacts health.Lifestyles
Lifestyles such an urban neighborhood where people commonly walk to work, shopping and recreation such that most people in the area walk a considerable number of miles in a week. This might be compared to a suburban neighborhood in the same city where people drive everywhere such that they have remarkably low rates of walking activity.Pollution
The distribution of pollution such as poor air quality near a major highway or port with better air quality in other parts of the same city.Social Inequality
Social inequality such as a pool of people who have no access to healthcare in an area where other people have access to high quality healthcare.Social Equality
The introduction of new levels of social equality such as a nation that makes university tuition free.Consumer Choice
Consumer choices such as subscriptions to media content. In the 1980s and early 1990s, before internet use was common, there was a sharp difference in media exposure based on cable TV subscriptions that were commonly sold in packages of channels. For example, teenagers who watched several hours of music videos a day versus those who had virtually no exposure or access to this media based on the cable subscriptions of their parents.History
Historical events such as a country that is divided into two completely different political systems due to war and conflict.Budgets
Budget cuts that result in a sudden change to services in a region. For example, a school district that suddenly changes average class size to 40 students per teacher where neighboring school districts remain at 25 students per teacher.Systemic Change
A complete change to a system. For example, the introduction of forest kindergartens in countries such as Denmark, Sweden and Germany whereby preschoolers have no classroom and learn in a natural setting filled with exploration, play and guided by a system of trust. This is based on a system of parental choice such that regular classroom instruction of preschoolers occurs in the same communities.Culture
Cultural practices such as a period of fasting whereby a population severely restrict their diet for cultural or religious reasons.Land Development
Human driven change to ecosystems such as a forest that is quickly converted to a large area of concrete facilities for a sports event. This might be used to model effects such as urban heat islands.Economic Conditions
Economic conditions such as an economic collapse that causes people to substitute a variety of goods. For example, the consumption of more rice and less meat.| Overview: Natural Experiment | ||
Type | ||
Definition | A real world situation that resembles an experiment without any intervention or control by experimenters. | |
Related Concepts | ||
