Providing up-to-date reporting on rosacea research is an important part of the National Rosacea Society’s mission to raise awareness and provide information on this common but often misunderstood disease. We try to explain scientific studies in plain, easy-to-understand language, but some terms may still need additional explanation. Here’s a guide to some of the key terms that are seen frequently in rosacea research but aren’t necessarily familiar to everyone. 

Blinded Studies: In order to prevent bias from influencing the results of a clinical trial, at least one of the participants in a clinical trial will not know if the patient is receiving an actual treatment or a placebo. This is referred to as a blinded study. There are several types of blinded studies but the most common are single-blinded, when only the investigator or the patient is aware of who is receiving active treatment versus placebo, and double-blinded, when neither the investigator nor the patient knows who is getting active treatment versus placebo. 

Comorbidity: The occurrence of two disorders or illnesses in the same person, at the same time or one after another. Comorbidity does not necessarily mean that one causes the other. 

Controlled study: A type of study design in which two groups are used for comparison purposes. 

Correlation: When two or more factors seem to occur and track at the same time. For example, heart disease and increasing age have a strong correlation because heart disease increases as one ages. Correlation does not mean that a change in one factor is the cause of the change in another factor. 

Meta-analysis: A quantitative analysis of a number of separate but similar studies in order to learn from the pooled data. Meta-analysis is often used in a review of available research. The larger data pool allows scientists to draw conclusions that may be statistically stronger than those provided by a more limited set of data. 

Placebo: An oral or topical formulation without the active ingredient, used for comparison with the active medication in controlled clinical studies. 

Statistical Significance: A measure of the probability that a relationship between variables would not be due to random chance. A study result is considered statistically significant if it is very unlikely (usually with 95 percent or higher confidence) that the result is due to chance. 

Variable: A variable is a factor within a study that can change, be unsteady or simply be different. For example, the age of a patient can be a variable. What impacts an 80-year-old may have a different result in a 20-year-old.