The quality of a product can be measured using predefined criteria such as reliability, durability, performance, functionality, and customer satisfaction. Reliability refers to the consistency of the product's performance over time, while durability measures the product's ability to withstand wear and tear. Performance assesses how well the product meets its intended purpose, and functionality evaluates the features and capabilities of the product. Customer satisfaction is a key indicator of quality, as it reflects how well the product meets the needs and expectations of the end user. By evaluating a product against these criteria, we can determine its overall quality and effectiveness.