Observational studies play an irreplaceable role in fields such as epidemiology, social sciences, psychology, and statistics. Although this type of research cannot control independent variables, the data and patterns it reveals can greatly influence our understanding of social phenomena and health issues. In many cases, randomized trials are often not possible for ethical or practical reasons, making observational studies the only viable option.
“Observational studies provide insights into “real world” use and practice. 」
Observational studies are primarily used to infer associations from a sample to a population, and there are many examples of these studies revealing unexpected truths. For example, scientists might conduct an observational study of the side effects of a drug. These studies often do not randomly assign subjects to treatment or control groups, but instead look for data from a known population. In this process, researchers must take into account potential biases, such as selection bias and omitted variable bias.
Observational studies come in many forms, but some important types include:
While observational studies cannot be used to make definitive statements about the safety, effectiveness, or efficacy of a practice, they can provide valuable information. For example:
"These studies are able to examine the benefits and risks of the practice in the general population."
Observational studies can provide hypotheses for subsequent experiments and community-level data for clinical practice, thereby designing more informative clinical trials.
While observational studies have their value, they often face challenges with bias. The following are common deviation issues:
Studies have shown that although observational studies cannot completely replace randomized controlled trials, in many cases the results of the two are similar. An updated review of the literature suggests that the results of observational studies are often not significantly different from those of randomized controlled trials, especially when the diversity of the samples and the relevance of the results are taken into account.
The advantage of observational studies is their breadth and flexibility, allowing them to study many topics that randomized trials cannot cover. However, the results of these studies still need to be interpreted with caution because the risk of bias caused by the lack of a random allocation mechanism always exists. This makes us wonder:
"In this case, how do we balance the challenges of observational research with the truth we can gain?"