different areas. Some members of Congress are elected by their peers to be officers of these committees. Further, Congress has ancillary organizations such as the Government Accountability Office and the Library of Congress to help provide it with information, and members of Congress have staff and offices to assist them as well. In addition, a vast industry of lobbyists helps members write legislation on behalf of diverse corporate and labor interests. The committee structure permits members of Congress to study a particular subject intensely. It is neither expected nor possible that a member be an expert on all subject areas before Congress. [ 101 ] As time goes by, members develop expertise in particular subjects and their legal aspects. Committees investigate specialized subjects and advise the entire Congress about choices and trade-offs. The choice of specialty may be influenced by the member's constituency, important regional issues, prior background and experience. [ 102 ] Senators often choose a different specialty from that of the other senator from their state to prevent overlap. [ 103 ] Some committees specialize in running the business of other committees and exert a powerful influence over all legislation; for example, the House Ways and Means Committee has considerable influence over House affairs. [ 104 ] Committees write legislation. While procedures such as the House discharge petition process can introduce bills to the House floor and effectively bypass committee input, they are exceedingly difficult to implement without committee action. Committees have power and have been called independent