Congressional hearings are the principal formal method by which committees collect and analyse information in the early stages of policy making. Whether legislative, oversight, investigative, or a combination of these, all hearings share common elements of preparation and conduct. House Rule XI sets down many of the regulations to which committee hearings must conform, including the quorum requirement, advance submission of witness statements, the opportunity for minority party members to call witnesses of their choosing, the five-minute rule for questioning witnesses, witness rights, the process for issuing a subpoena, the procedure for closing a hearing to the public, and the broadcast of hearings and media behaviour. Committees have broad latitude in how they hold hearings, in part because they adopt their own rules of procedure. These rules may amplify and supplement House rules, but cannot contravene them. Customs of committees not embodied in rules also vary considerably among committees. Committees usually plan extensively for hearings. On the day of a hearing, a committee needs a quorum to conduct business. While most hearings are open to the public, a committee may vote to close a hearing for a reason specifically stated in House rules. Following a hearing, committee staff may prepare a summary of testimony, draft additional questions for the day's witnesses, and begin to ready the hearing transcripts for printing and publishing to the Web. Transcripts generally are printed, along with supplemental materials approved by the committee, although printing is not required.