…n Group defines usability as a quality attribute that assesses how easy user interfaces are to use. The level of usability depends on five aspects: learnability, satisfaction, efficiency, memorability, and errors. Learnability stands for how easy users can attain tasks during the first usage and satisfaction is how pleasant the usage process is. Efficiency is determined by users’ ability to accomplish a task quickly while memorability depends on time which people need to re-establish their proficiency after a period of not using a product. And finally, designers track the number of errors users make and how easily they can learn from these mistakes.