Redlining is the practice of denying or increasing the cost of services, such as banking, insurance, access to jobs, access to health care, or even supermarkets to residents in certain, often racially determined, areas. The most devastating form of redlining, and the most common use of the term, refers to mortgage discrimination. Data on house prices and attitudes toward integration suggest that in the mid-20th century, segregation was a product of collective actions taken by whites to exclude blacks from their neighborhoods.