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Research Brief

Key Findings

  1. Researchers modeled the Army's ability to regenerate its active component (AC) end strength over a five-year period in two scenarios — starting from a Total Army of 980,000 (450,000 AC) and starting from a Total Army of 920,000 (420,000 AC) — such that the Army could provide the number of deployable troops available at the end of the last conflict.
  2. Achieving the target end strength is possible in the time frame for both scenarios, but the scale of expansion would exceed recent experience and would require the robust use of existing policy levers, including, under most conditions, the acceptance of a higher share of low-quality recruits.
  3. Regeneration entails less risk in the 980,000 scenario than in the 920,000 scenario; if recruiting conditions are highly favorable, it may be possible to achieve regeneration targets without reducing the share of high-quality recruits when starting from 980,000.
  4. The difficulty of expansion will largely depend on prevailing external conditions, most notably whether the expansion happens during good or bad economic conditions.
  5. If the full target of deployable troops is required immediately, the reserve components would need to be mobilized at an unprecedented rate, potentially operating at mobilization-to-dwell ratios of under 1:3 while the AC is being rebuilt.

The 2014 Army Posture Statement considered two future Army end strengths: one that included an active component (AC) of 450,000, as part of a Total Army of 980,000, and one that included an AC of 420,000, as part of a Total Army of 920,000.

These force sizes would represent large cuts that call into question the Army's ability to restore or "regenerate" itself to previous strength levels in a timely way, should the nation require it to do so. This brief summarizes work that examined the Army's ability to regenerate its AC end strength over a five-year period to meet the demands of large-scale, protracted contingency operations of about the same scale as those in Iraq and Afghanistan over the past decade and a half.

What Approach Did We Use?

To assess the Army's ability to regenerate, we started with either a 450,000 or 420,000 AC base and postulated that the AC would have to expand to a degree that enabled the Total Army to produce the same amount of capacity it had at the end of fiscal year (FY) 2009 — a 550,000 AC — when it reached its targets for expansion under the Grow the Army campaign. We focused our efforts on enlisted soldiers, because previous work indicates that one of the most critical constraints on regeneration will likely be enlisted accessions.

To reach this target, we estimated that the AC would have to expand by about 95,000 enlisted soldiers under the 980,000 (450,000 AC) scenario and by about 127,000 enlisted soldiers for the 920,000 (420,000 AC) scenario. Both options have somewhat larger AC peak strengths than the AC peak strength of 550,000 that existed in FY 2009 — about 570,000 for the 980,000 scenario and 580,000 for the 920,000 scenario — but since downsizing was also planned for the reserve components (RC), we assumed that the AC would need to compensate for the substantial numbers of reservists no longer available.

We then developed a conceptual model of regeneration that reaches target end strength after a number of years by applying various policy levers to affect the flow of soldiers into and out of the force. The figure below shows the conceptual model and timeline used for AC regeneration.

The top of the figure illustrates how the Army can affect flows of soldiers by using different accession and retention policies, including how it allocates funding and personnel to the recruiting and retention efforts. How many recruiters the Army has, how much it spends on advertising and incentives, and what enlistment eligibility criteria it imposes have important effects on recruiting. The figure also shows how the Army can influence the shape of the force by adjusting promotion and retention policies, including the size and number of reenlistment bonuses.

Conceptual Model and Conceptual Timeline of AC Regeneration

Conceptual Model and Conceptual Timeline of AC Regeneration

Because the Army does not recruit in a vacuum, we also posited different external environments that affect the Army's ability to attract recruits from the civilian population. These environments include such things as the job market (a bad one is generally good for Army recruiting and vice versa) and how the civilian population might view a given conflict.

The bottom of the figure shows the conceptual timeline. We assumed that the conflict starts, and the need for regeneration is recognized, at the start of Year 1. Existing soldiers are immediately trained and deployed, but experience suggests that it will take time to obtain authorization for increased troop levels and to execute that plan. For example, even if troop authorizations were immediately increased, it would take several months to increase the number of recruiters and train them, to obtain additional advertising slots, and to see results from the increased advertising efforts. Although higher enlistment and reenlistment bonuses could be implemented more quickly, it might also be several months before they took effect. Thus, although existing troops are trained and deployed during the first year, we assumed that the major increases in accessions and retention are seen during Years 2, 3, and 4.

What Did We Find in Applying Our Approach?

The table summarizes the key results for regenerating from the two future end strengths considered in the 2014 Army Posture Statement. Each scenario includes the results of relaxing or not relaxing recruiting standards for enlistment and also describes how favorable, average, and unfavorable recruiting conditions affect the Army's ability to meet end strength targets. On the right, the table depicts the effects of manpower shortfalls on the RC in terms of the ratio of time mobilized to time demobilized over the period. These effects can differ, depending on whether operational demands are high from the outset or increase more gradually. In both scenarios, we assume that the most robust recruiting and retention policy levers consistent with recent history are put in place to increase capacity.

Summary of Results for the Two Scenarios

Scenario Recruiting Standards Recruiting Conditions Shortfall at End of Year 5a Cumulative RC Mobilization-to-Dwell Ratiob
Immediate Demand Gradual Buildup
At Year 3 At Year 6 At Year 3 At Year 6
920,000 Lesser enlistment eligibility Favorable 25,578 1:1.6 1:2 1:2.4 1:2.5
Average 39,975 1:1.6 1:1.9 1:2.4 1:2.4
Unfavorable 54,620 1:1.6 1:1.9 1:2.4 1:2.3
Greater enlistment eligibility Favorable None 1:1.6 1:2.1 1:2.4 1:2.7
Average None 1:1.6 1:2.1 1:2.4 1:2.7
Unfavorable None 1:1.6 1:2.1 1:2.4 1:2.6
980,000 Lesser enlistment eligibility Favorable 1,334 1.2 1:2.5 1:2.8 1:2.9
Average 15,236 1:2 1:2.4 1:2.8 1:2.8
Unfavorable 30,688 1:2 1:2.3 1:2.8 1:2.7
Greater enlistment eligibility Favorable None 1:2 1:2.5 1:2.8 1:3
Average None 1:2 1:2.5 1:2.8 1:3
Unfavorable None 1:2 1:2.5 1:2.8 1:3

a Shortfalls relative to the need for 95,000 new enlisted soldiers in the 980,000 scenario and 127,000 new enlisted soldiers in the 920,000 scenario.

b We estimated the cumulative MOB:Dwell ratio; for example, if the ratio is 1:3 at Year 6, the RC is not necessarily operating at 1:3 in Year 6 but has been operating at an average ratio of 1:3 over the previous six years.

Starting from a Total Army of 920,000 would likely result in a shortfall at the end of Year 5 if enlistment eligibility is not expanded, regardless of whether recruiting conditions are favorable or unfavorable. When starting from 980,000, it may be possible to almost eliminate the shortfall by the end of Year 5 if enlistment eligibility is not expanded, but only if recruiting conditions are favorable. We also see that external conditions matter a lot. As the table shows, the range of the shortfall in both scenarios varies significantly depending on whether recruiting conditions are favorable, average, or unfavorable. As shown in the first four columns, in both the 920,000 and 980,000 scenarios and assuming greater enlistment eligibility (a lower share of high-quality recruits, more waivers, and more prior-service accessions), it may be possible to recruit the manpower needed to both sustain and expand the force — all the rows in the table that show no projected shortfall at the end of Year 5. Doing so is more challenging for the 920,000 scenario than for the 980,000 one.

Also, as shown on the right side of the table, regeneration would stress the RC, especially when starting from a Total Army of 920,000. If the full target of deployable forces is required immediately, the RC would need to rotate at a cumulative mobilization-to-dwell ratio of well under 1:3. Note that this analysis makes the simplifying assumption that RC manpower is perfectly fungible — that a radar repairman can function effectively as an armor crewman with no additional training required. In reality, the stress on certain elements of the RC would be even greater. A gradual buildup in deployable troop strength would not require the same level of mobilization but would nonetheless stress the RC. Although demand for RC forces would decline as the AC expanded, RC forces would still have been deployed at or above a cumulative ratio of 1:3 at the end of the sixth year. While the RC can sustain this level of deployment from a force structure perspective, it would place these components under substantial stress; thus, congressional and public support might be difficult to muster or sustain.

What Do We Recommend?

We propose the following recommendations, which lie largely within the remits of the Departments of Defense and Army:

  • Develop and resource specific capabilities to enable regeneration. The Army should explore a range of scenarios to make informed decisions about what specific capabilities it would require to successfully regenerate the AC under the selected scenarios and to determine which of the capabilities exist now and which need to be developed.
  • Assess alternative ways to posture the Army for regeneration. In the past, the Army has considered different approaches to expansion (establishing cadre formations, drawing manpower from the generating force, etc.). The Army should explore which of these approaches, or what combination thereof, best positions it to expand rapidly.
  • Prepare the RC for rapid and high-frequency deployment. Failure to prepare all stakeholders risks disruption at the time of crisis. Such preparation may involve changing policies that limit RC employment, including the DoD policy limiting mobilization to one year.
  • Maintain certain critical skills in the Army today to reduce the stress placed on the Army during regeneration. Our analysis treated enlisted soldiers as fungible, but regeneration will require accessing and developing some soldiers with specialized skills that may be impossible to build up in a short time. Maintaining a wedge of additional midgrade leaders, along with a sufficient number of individuals in military occupational specialties with a long lead time for training or skills development, could reduce the risk associated with a potential regeneration.
  • Maintain Army capacity for contingency contracting, which the Army has depended on in recent conflicts. As Army operating forces decrease, the need to contract out support and sustainment capacity may well increase and certainly will not decrease.
  • Develop contingency plans. Although the analysis did not identify any definitive limit to the Army's ability to regenerate at the speed and on the scale described here, these efforts are fraught with risk. Thus, as the Army plans for rapid AC expansion, it should also develop contingency plans, which will almost certainly hinge on a much higher degree of mobilization of the Army's RC, if that AC expansion falters.
  • Decide early. The analysis assumes that the decision to regenerate rapidly would be made at the start of the conflict and that all policy levers would be in place by the end of the first year of the conflict to deliver the first meaningful increment of capability by the third year. Thus, a decision to go to war should be a decision to expand the Army.

These recommendations require public support to succeed. Political leaders — especially the President — must be prepared to expend political capital to generate and sustain the necessary level of public support and create a context in which measures to expand the Army can succeed.

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