The Joint Strike Fighter (JSF) program seeks to produce 3 aircraft variants for the Air Force, Navy, Marine Corps, and 8 international partners. The total investment for JSF approaches $1 trillion to acquire and maintain 2,458 aircraft. There has been an annually review of the JSF program since 2005. The prior reviews have identified a number of issues and recommended actions for reducing risks and improving the program¿s outcomes. This report, the 4th under the mandate, focuses on the program¿s progress in meeting cost, schedule, and performance goals; plans and risks in development and test activities; the program¿s cost-estimating methods; and future challenges facing the program. Includes recommendations. Charts, tables and graphs.