Budget Process Improvement Act of 2013

Budget Process Improvement Act of 2013 - Amends the Congressional Budget Act of 1974 (CBA) to require: (1) the Director of the Congressional Budget Office (CBO) to include a descriptive analysis for the second decade budget impact of a measure when submitting a cost estimate of it, and (2) the Joint Committee on Taxation (JCT) to provide such an analysis when its submitting revenue estimates to CBO.

Requires the Office of Management and Budget (OMB) to publish a report on the size, scope, risk, and cost of the contingent federal liabilities, including the implicit guarantees to government sponsored enterprises (GSEs) such as the Federal National Mortgage Association (Fannie Mae) and the Federal Home Loan Mortgage Corporation (Freddie Mac).

Requires the Secretary of the Treasury to conduct performance reviews of JCT-identified tax expenditures on an ongoing basis.

Requires OMB to: (1) develop a proposal for the implementation of an accrual-based accounting system for certain portions of the budget, and (2) report to Congress on legislation necessary to implement such system.

Requires the JCT to publish a report that projects annual federal revenues by source over the next 10 fiscal years and includes a discussion of the assumptions used to project such revenues.

Amends the CBA to require: (1) biennial (instead of annual) budget resolutions, (2) biennial appropriations Acts, and (3) biennial government strategic and performance plans.

Makes conforming amendments to the Rules of the House of Representatives.

Defines the budget biennium as the two consecutive fiscal years beginning on October 1 of any odd-numbered year.

Requires: (1) a federal agency, upon request by a congressional committee, to provide appropriate information regarding its appropriations requests and program administration; (2) the Comptroller General to furnish to such committee summaries of any audits or reviews of such program which the Comptroller General has completed during the preceding six years; and (3) the Comptroller General, Director of the Congressional Budget Office (CBO), and the Director of the Congressional Research Service (CRS) to furnish such committee appropriate information, studies, analyses, and reports.

Requires the Director of the Office of Management and Budget (OMB) to determine and report to Congress on the impact and feasibility of changing the definition of a fiscal year, and the budget process based on that definition, to a two-year fiscal period with a biennial budget process based on such period.

Requires the President's budget submission for FY2016 to include: (1) an identification of the budget accounts for which an appropriation should be made for each fiscal year of the FY2016-FY2017 biennium, and (2) budget authority that should be provided for each such fiscal year for the budget accounts.

Directs: (1) the House and Senate committees, during the first session of the 114th Congress, to work with the Comptroller General to develop plans to transition program authorizations to a multi-year schedule; and (2) the Comptroller General, during such Congress, to continue to provide assistance to Congress with respect to programmatic oversight, and in particular to assist the congressional committees in designing and conforming programmatic oversight procedures for FY2016-FY2017 biennium.