One of the most difficult problems in managing for results has been the development of meaningful performance measures when external factors significantly influence the outcomes the agency strives to influence. Isolating federal contributions can be difficult when economic, social, or technological trends have a dominant affect on the ultimate result. It is not surprising that moving from output measures to outcome measures has proven to be a difficult step to take within the organizational culture of government. Public sector work by its nature leads ultimately to societal outcomes, and many societal outcomes are driven by an almost unlimited range of forces outside the control of a program or agency. Regulatory and economic development programs classically confront the problem of external influences, but external factors complicate almost all the programs in government.
Environmental initiatives dealing with complex ecosystems face great uncertainty in their outcomes.
A vigorous economy spurs consumption and travel, increasing pollution and traffic fatalities while frustrating environmental and safety programs. External forces affect almost every outcome measure in some way. Program managers are often reluctant to deal with outcome measures that are outside their immediate control. Yet societal outcomes are the reason why government is charged with resources and authority. If vehicle and passenger-miles traveled rise with the economy, then the public will expect its government to initiate new ways to control the unintended results.