In short, confounders confuse the results because they provide alternative explanations for the differences.ĭespite the limitations, an observational study can be a valid approach. If there are differences in health outcomes at the end of the study, it’s possible that these healthy habits actually caused them rather than the vitamin consumption itself. These healthy habits are confounding variables. People who use vitamin supplements voluntarily will tend to have other healthy habits that exist at the beginning of the study. Imagine an observational study that compares people who take vitamin supplements to those who do not. Learn more about internal and external validity. Performing an observational study can decrease the internal validity of your study but increase the external validity. If an experiment does not account for confounding variables, confounders can bias the results and create spurious correlations. Consequently, confounders can be the actual cause for differences in outcome at the end of the study rather than the primary variable of interest. Because there is no random process that equalizes the experimental groups in an observational study, confounding variables can systematically differ between groups when the study begins. A confounding variable, or confounder, correlates with both the experimental groups and the outcome variable. While observational studies get around the inability to assign subjects randomly, this approach opens the door to the problem of confounding variables. It’s unrealistic to enforce the treatment and control protocols over such a long time for so many people! Drawbacks of Observational Studies However, the study assesses vitamin consumption in 40,000 participants over the course of two decades. It’s possible to use random assignment to place each subject in either the vitamin treatment group or the control group. Later in this post, we’ll closely examine a quantitative observational study example that assesses vitamin supplement consumption and how that affects the risk of death.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |