Effect Size: Effect size refers to the magnitude or intensity of a statistical phenomenon or experiment result. In simpler terms, it measures how big of an effect a certain factor or variable has in a study or test. It provides context for statistical significance and can help you to understand the practical significance, or real-world impact, of your findings. In marketing, it may describe the extent to which a particular marketing campaign or strategy has impacted sales, customer engagement, or any other target metric.