The most reliable scientific approach to test a hypothesis is the experiment. The primary goal of experimentation is to determine causal relationships between specific conditions or interventions and the outcomes being observed. For example, suppose we want to examine the effect of radiofrequency microneedling on reducing facial acne scars. If participants are also taking oral isotretinoin during the treatment period, any improvement in skin appearance might be influenced by both interventions. In this case, isotretinoin becomes a confounding variable, making it difficult to determine whether the effect was due to the microneedling itself, the medication, or a combination of the two. Furthermore, skin improvement could be the result of spontaneous healing or other cosmetic treatments the participant may have received concurrently. Experiments must therefore be carefully designed to control for such confounding variables. Although it is rarely possible to eliminate all confounders in clinical studies, experimental methods provide the strongest evidence to support causal relationships between variables.