Jim is a senior member of the House Ways and Means Committee, which is responsible for writing tax law. Since the Ways and Means Committee is also responsible for dealing with any and all tax-related matters, nearly every issue falls under the Committee's jurisdiction – this includes health care, Social Security, economic development, trade, the environment, housing, and personal and corporate taxes, just to name a few. Below is the official description of the Committee, as well as the Subcommittees of which Jim is a member. 

House Ways and Means Committee, Senior Member
The Committee on Ways and Means is the oldest committee of the United States Congress, and is the chief tax-writing committee in the House of Representatives. The Committee derives a large share of its jurisdiction from Article I, Section VII of the U.S. Constitution which declares, "All Bills for raising Revenue shall originate in the House of Representatives." The Committee exercises jurisdiction over revenue and related issues such as tariffs, reciprocal trade agreements, and the bonded debt of the United States.  Revenue-related aspects of the Social Security system, Medicare, and social services programs also fall under the Ways and Means Committee's jurisdiction.

• Subcommittee on Health, Ranking Member
  The jurisdiction of the Subcommittee on Health includes bills and matters that relate to programs providing payments for health care, health delivery systems, or health research, including health care programs of the Social Security Act and tax credits and deductions dealing with health insurance premiums and health care costs.

House Budget Committee, Senior Member
The Committee on the Budget is responsible for drafting the annual budget resolution and reconciling all budget plans between the legislative and executive branches. The budget resolution establishes aggregate levels of spending and revenue, the deficit or surplus, and public debt. The Committee also provides independent analyses of all federal spending through the Congressional Budget Office. The Committee was established in 1974 and derives from the constitutional mandate to fix control of the nation’s purse in the U.S. House of Representatives.