The DAGMAR approach defines goals for measuring advertising effectiveness. It was developed by Russel Colley in 1961 to distinguish 52 advertising goals related to sales, image, attitude, and awareness. The approach involves defining goals that are specific, have a defined target audience and measurement procedure, benchmarks for achievement, and are written down. It focuses on matching communication tasks to audience involvement levels related to awareness, comprehension, attitude, and action. While useful historically, the DAGMAR approach faces challenges related to quantifying sales goals, measurement difficulties, and external influences.