There is a consistent refrain from advocates of higher defense spending that the spending limits imposed by the Budget Control Act of 2011 are diminishing America’s military readiness. Diminished readiness is an understandable concern. While the world is a relatively safe place despite what one might infer from cable news, and while America is particularly safe given its great power and favorable geography, things can still go wrong.

The implication of this argument however is that increased defense spending is the key to readiness. As previously noted on this blog, there are reasons to think increased defense spending will only exacerbate the difficulties the Department of Defense currently faces. But when it comes to readiness, the short answer to the title of this post is that nobody really knows how defense spending affects it because the military lacks good metrics for determining it.

Writing recently in Strategic Studies Quarterly, Todd Harrison, defense budget guru at the Center for Strategic and Budgetary Assessments, persuasively argues that the military needs a new way of determining readiness. The current system, as Harrison notes, is based largely on “inputs” with no indication of what those inputs achieve. By inputs, Harrison means measurable actions: flying hours for the Air Force, steaming days for the Navy, tank miles for the Army, and training events for the force as a whole. These inputs however say little about what the services gain from them.

Are pilots more or less skilled in air-to-air combat based on the number of hours they fly? Based on the current system the military uses to determine readiness, the main determining factor is whether the Air Force has adequate resources—and by resources, it means funds—to undertake those training hours. It does not address whether the prescribed number of hours actually makes Air Force pilots more proficient. In describing the military’s Status of Readiness and Training System (SORTS), Harrison articulates the problem thusly:

The SORTS does not attempt to measure the ability of units to carry out the missions assigned to them. Instead resources are used as a proxy—a stand-in measure—for performance. The SORTS assumes, by definition, that if all resource areas meet target levels then a unit will be fully ready. It further assumes that the target levels of resources set by the services are correct, both in the total level required in each resource area and in the relative weighting of resources among the four areas. Yet the target levels could be excessive, insufficient, or irrelevant to actual readiness.

This system creates a pernicious circular logic. If the system is based on inputs, and inputs are based on resources, readiness by the military’s definition is merely a factor of a certain level of defense spending. Harrison sums up the military’s system succinctly: “a reduction in readiness inputs will result in a reduction in readiness inputs.” Prior efforts to reform this system have only added a subjective commander’s assessment without addressing its underlying failings.

Harrison recommends replacing the current readiness metrics with an experimental system of strategy-based metrics. Based on the outcome of the recommended experiments, it might be determined that defense spending is too low or that strategy needs to be adjusted due to resources constraints.

Whether one agrees with his proposed system or not—and it has apparently caused some consternation in at least one military service—it is clear a change is necessary. A system that determines its readiness simply as a function of defense spending will be forever in need of increased spending, even if such spending does not actually improve its readiness.