Understanding Psychiatric Research and Words, A Little Better
A glossary-based post.
A while back, I wrote a guide for coworkers to help them understand “what the heck I was talking about.” What follows is that guide, with some light rewrites, I hope it proves useful.
Sound Smart When Discussing Research with Your Friends
Here are the terms used to describe research studies and what they mean.
Efficacy: Does the treatment work in a select group of people? (Almost all treatments are approved based on efficacy only).
Effectiveness: Does the treatment work in the real world?
Statistical Significance: Statistical significance refers to the likelihood that the difference in the data (like differences between groups or relationships between variables) is not due to chance. This is often evaluated using a p-value. If the p-value is less than a predetermined threshold (often 0.05), the result is declared statistically significant. However, statistical significance doesn't tell us anything about the magnitude or importance of the difference or relationship. A small, unimportant difference can be statistically significant if the sample size is large enough.
Effect Size: Effect size, on the other hand, is a measure of the magnitude of the difference or relationship. Unlike statistical significance, it is not influenced by sample size. Effect sizes can be very helpful in understanding the practical or clinical importance of research findings. For instance, a medication might significantly reduce symptom severity compared to a placebo (statistical significance), but if the reduction is very small (small effect size), it might not make a meaningful difference in patients' lives.
In short, statistical significance addresses the question, "Is it likely that there's a true effect or difference?" while effect size addresses the question, "How big or important is the effect or difference?" It's important to consider both when interpreting research findings. The Muir-Skee Lo Emotionally Corrective Equation was built to solve this problem for general audiences.
Placebo vs. Sham: A placebo is an inactive substance or treatment that looks just like, and is given in the same way as an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo. On the other hand, a sham is a procedure or treatment that is intended to mimic as closely as possible an intervention but does not confer any real treatment. It is generally used in clinical trials for devices and surgical interventions.
FDA Approval vs. Clearance: FDA approval is required for new drugs and new, or “de-novo, medical devices. This process involves rigorous testing and review to ensure safety and effectiveness.
FDA clearance, on the other hand, is a lower-level review process that is used for medical devices that are considered to be a lower risk or that are substantially similar to a device that is already legally on the market.