From the Executive Summary: "This report introduces the main steps through which a bill (or other item of business) may travel in the legislative process-from introduction to committee and floor consideration to possible presidential consideration. However, the process by which a bill can become law is rarely predictable and can vary significantly from bill to bill. In fact, for many bills, the process will not follow the sequence of congressional stages that are often understood to make up the legislative process."
CRS Report for Congress, R42843
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html