The AIDA model is a classic framework describing how advertising leads a recipient towards a purchase through four stages: Attention, Interest, Desire and Action. It assumes that effective communication should, in turn, catch attention, spark interest, build a want and prompt action, and it still shapes how messaging is planned. The model was devised in the late nineteenth century. Worth knowing: modern purchase journeys are rarely this linear. Consumers compare offers repeatedly, look for opinions, return to earlier stages and use several channels at once, so alongside AIDA people now use models that capture this behaviour better, such as Google’s Messy Middle, 5A or See-Think-Do-Care.