Back in the early 80s, as the Army was trying to get past the low morale and poor quality of the first years of the post-Vietnam All Volunteer Force, an interesting experiment was tried to boost unit cohesion and esprit de corps. COHORT- Cohesion Operational Readiness and Training.
The Army’s normal peacetime personnel replacement system since the end of World War One has been an individual system. That is, each unit would detach individuals to their next assignment or at the end of their enlistments, and in turn receive individuals to bring them back up to strength. Indeed, during the Vietnam War, even units deployed and fighting utilized this system. And many of the commanders in the Army during the early 80s remembered that the individual replacement system in Vietnam caused a lot of headaches. An individual would enlist or be drafted, run through training, and suddenly find himself in Vietnam assigned to a unit in which he didn’t know a single soul, and who generally didn’t accept newcomers until they had proven themselves.
In an effort to mitigate these issues, the Army tried a unit replacement scheme for certain combat arms battalions. . That is, a group of soldiers would remain together, from their first day in the Army to the end of their first enlistment.*
The way it worked was like this- throughout the recruiting world, young men enlisting, let’s say, for the infantry would be offered the COHORT option for a 3 year enlistment. About 500 enlistees would be assigned the same reporting date, and would form the bulk of a COHORT battalion. About they time they all shipped out, an experienced cadre of officers and NCOs would form at the eventual stateside duty station of the COHORT battalion to prepare for the unit’s activation. Meanwhile, our gaggle of enlistees would go through processing, basic and advanced individual training at Ft. Benning, and then take a short leave. After their leave was up, they’d report to their duty station and fall in on the cadre. In short order, you had a brand new infantry battalion. And the new enlisted soldiers of this battalion all knew one another from their basic training. The same crowd you trained with at Benning would be your squad and platoon mates. Almost immediately, the battalion would begin building on the individual skills the enlistees had learned at Ft. Benning to forge unit level collective skills.
After about a year of training, the COHORT battalion would then be transferred overseas for about 2 years, either in Germany, Hawaii, or Korea. At the end of the three year enlistment period, the unit would be replaced by another COHORT battalion, most folks would leave the Army, and those that reenlisted would move on to other assignments, or even serve as cadre for another newly forming COHORT unit.
And it wasn’t a crazy idea. Indeed, in many ways, that’s how the Army cranked out division after division in the huge expansion of WWII. A cadre of about 1500 officers and NCOs would be given 14,000 newly enlisted Privates, a year or so of time to train, and then they’d ship out to one of the war theaters.
But COHORT was never really popular in the Army. The big disadvantage was that the end strength of the units and the Army as a whole remained the same, but for at least an entire year, the COHORT battalion just didn’t have the level of unit training needed to be combat ready. It takes a lot of training to build up the collective skills to fight and win, and you can’t just take a group of folks straight out of basic training and say “GO!” Given that year needed to train, and the three year enlistment period, it would naturally follow that about a third of any COHORT based force at any given time just wasn’t ready for combat.
A normal unit under the individual replacement system would see its readiness increase and decline during the same three year cycle, but would never spend an entire year unavailable for combat. It might have a good deal of personnel turnover, but not the wholesale replacement of its entire human capital.
Now, the rule of thumb is 3 units needed for one deployed. That is, in a normal unit rotation cycle, one unit is deployed, one is recovering from its deployment, and one is training up for deployment. But the reality is that in an extreme pinch (like the Warsaw Pact rolling over the border) all three of a normal individual replacement unit could deploy and fight. There might be some folks in the unit that weren’t up to speed, but the basic building blocks of the unit were well enough trained to be a net positive asset in combat.
In a normal unit, there are large numbers of “old hands” PFCs and Specialists with two or even three years of service that a junior NCO leads, but doesn’t have to watch constantly. They also lend a hand in bringing the newest troops up to speed on unit standards and techniques. But in a COHORT unit, there was no institutional knowledge at the enlisted level. For them, everything was new, and their only resource was the NCO cadre. That’s great. As long as the NCO was there. But what if he was at school, or on sick leave? Or for that matter, just a lousy teacher and doing a bad job of training? There was a lack of tribal knowledge in a COHORT unit. Just about the time a COHORT unit gained that knowledge and got to be good at its job, its 3 year enlistment term expired. And the cycle started over again.
COHORT died a quiet death sometime in the early 90s. Around the time it got rolling in the 80s, the Reagan buildup actually addressed most of the problems with Army personnel that COHORT was intended to address. And it never found a great deal of acceptance from many unit commanders. It was a lot of hassle to bed down a brand new unit stateside, only to see them leave in a little over a year, and have to go through the bed down process again.
The unit replacement program however, did have some impact. The need for strong unit cohesion was well understood, and the shortcomings of the individual replacement system during wartime were not to be repeated. Unlike in Vietnam where units were stationed there for years, and over the course of a year would see almost complete personnel turnover, today the Army deploys units to war as units. They leave together, and come back together after a year (or 15 months, if you were lucky enough to get caught up in the Surge in Iraq). During that time, as much is done as possible to minimize personnel turbulence, and this build unit cohesion.
*The COHORT program was in fact one of the driving factors in the adoption of One Station Unit Training or OSUT for combat arms initial entry training. If you were going to run 500 guys through basic together, you might as well run them through the AIT phase together, and with the same drill sergeants.