Evaluating the validity of a therapy study
A web-based Duke University tutorial explaining how to address the question: are the results of the study valid?Key Concepts addressed:
- 2-2 Comparison groups should be similar
- 2-3 Peoples' outcomes should be analyzed in their original groups
- 2-4 Comparison groups should be treated equally
- 2-5 People should not know which treatment they get
- 2-7 All should be followed up
This tutorial will focus on the question: are the results of the study valid? The issue of validity speaks to the “truthfulness” of the information. The validity criteria should be applied before an extensive analysis of the study data. If the study is not valid, the data may not be useful.
The evidence that supports the validity or truthfulness of the information is found primarily in the study methodology. Here is where the investigators address the issue of bias, both conscious and unconscious. Study methodologies such as randomization, blinding and follow-up of patients help insure that the study results are not overly influenced by the investigators or the patients.
Evaluating the medical literature is a complex undertaking. This session will provide you with some basic criteria and information to consider when trying to decide if the study methodology is sound. You will find that the answers to the questions of validity may not always be clearly stated in the article and that readers will have to make their own judgments about the importance of each question. Read more