Washington Retrospective Rating Business and Industry Category Guide is a guide used by employers in Washington State to determine their business and industry classification for workers' compensation retrospective rating plans. The guide is divided into four categories: (1) Manufacturing and Processing; (2) Construction and Building; (3) Trade and Services; and (4) Other. Each category is further broken down into sub-categories. For example, Manufacturing and Processing is divided into sub-categories such as Automotive Manufacturing, Chemical Manufacturing, and Metal Manufacturing. The guide also provides information on the expected risk of injury associated with each business and industry classification. This information can be used by employers to help determine the best retrospective rating plan for their business.