"A hearing is a meeting or session of a Senate, House, joint, or special committee of Congress, usually open to the public, to obtain information and opinions on proposed legislation, conduct an investigation, or evaluate/oversee the activities of a government department or the implementation of a Federal law. In addition, hearings may also be purely exploratory in nature, providing testimony and data about topics of current interest. Most congressional hearings are published two months to two years after they are held." (GPO). The Government Printing Office prints the official, complete version, and not all hearings are published.
Committee reports are analyses and recommendations regarding legislation, and are very useful for ascertaining the purpose or intent of a bill. When the House and Senate cannot reconcile their different versions of a bill, a committee with members from both houses works out a compromise and issues a conference committee report.