Title: Observational Studies | Boundless Statistics
Headings: Observational Studies
Observational Studies
What are Observational Studies?
Learning Objectives
Key Takeaways
Key Points
Key Terms
Usefulness and Reliability of Observational Studies
The Clofibrate Trial
Learning Objectives
Key Takeaways
Key Points
Key Terms
Placebo-Controlled Observational Studies
Results of The Coronary Drug Project
Confounding
Learning Objectives
Key Takeaways
Key Points
Key Terms
Confounding Variables
Types of Confounding
Decreasing the Potential for Confounding
Sex Bias in Graduate Admissions
Learning Objectives
Key Takeaways
Key Points
Key Terms
Sex Bias at the University of California, Berkeley
Aggregate Data:
Department A
Department B
Department C
Department D
Department E
Department F
Confounding Variables and Simpson’s Paradox

Content: Observational Studies | Boundless Statistics
Observational Studies
What are Observational Studies? An observational study is one in which no variables can be manipulated or controlled by the investigator. Learning Objectives
Identify situations in which observational studies are necessary and the challenges that arise in their interpretation. Key Takeaways
Key Points
An observational study is in contrast with experiments, such as randomized controlled trials, where each subject is randomly assigned to a treated group or a control group. Variables may be uncontrollable because 1) a randomized experiment would violate ethical standards, 2) the investigator may simply lack the requisite influence, or 3) a randomized experiment may be impractical. Observational studies can never identify causal relationships because even though two variables are related both might be caused by a third, unseen, variable. A major challenge in conducting observational studies is to draw inferences that are acceptably free from influences by overt biases, as well as to assess the influence of potential hidden biases. A major challenge in conducting observational studies is to draw inferences that are acceptably free from influences by overt biases, as well as to assess the influence of potential hidden biases. Key Terms
causality: the relationship between an event (the cause) and a second event (the effect), where the second event is understood as a consequence of the first
observational study: