Command over the U.S. Armed Forces is established in the Constitution. The sole power of command is vested in the President by Article II as Commander-in-Chief. The Constitution presumes the existence of "executive Departments" headed by "principal officers", whose appointment mechanism is provided for in the Appointments Clause. This allowance in the Constitution formed the basis for creation of the Department of Defense in 1947 by the National Security Act. The DoD is headed by the Secretary of Defense, who is a civilian and member of the Cabinet. The Defense Secretary is second in the U.S. Armed Forces chain of command, with the exception of the Coast Guard, which is under the Secretary of Homeland Security, and is just below the President and serves as the principal assistant to the President in all defense-related matters.[14] Together, the President and the Secretary of Defense comprise the National Command Authority, which by law is the ultimate lawful source of military orders.[15]
It is critical to know how ASVAB scores are calculated and what they are used for.  The Armed Services Vocational Aptitude Battery (ASVAB) tests are used to identify whether a candidate is qualified to enlist in a particular branch of the U.S. Military.  The ASVAB test is also used to determine which military jobs (referred to as MOS for Military Occupational Specialties) a candidate is best suited for.  ASVAB scores can also be used by test takers to help explore which careers they may be a good fit for them – whether they go into the military or not. While no one officially passes or fails the ASVAB, each branch of the military has specific minimum scores required for enlistment.  Your scores also affect the type of military job, enlistment bonuses and salary you are eligible for.
Soldiers and armies have been prominent in popular culture since the beginnings of recorded history. In addition to the countless images of military leaders in heroic poses from antiquity, they have been an enduring source of inspiration in war literature. Not all of this has been entirely complementary, and the military have been lampooned or ridiculed as often as they have been idolised. The classical Greek writer Aristophanes, devoted an entire comedy, Lysistrata, to a strike organised by military wives, where they withhold sex from their husbands to prevent them from going to war.

After enlistment, new recruits undergo basic training (also known as "boot camp" in the Marine Corps, Navy and Coast Guard), followed by schooling in their primary Military Occupational Specialty (MOS), rating and Air Force Specialty Code (AFSC) at any of the numerous training facilities around the United States. Each branch conducts basic training differently. The Marine Corps send all non-infantry MOS's to an infantry skills course known as Marine Combat Training prior to their technical schools. Air Force Basic Military Training graduates attend Technical Training and are awarded their Air Force Specialty Code (AFSC) at the apprentice (3) skill level. All Army recruits undergo Basic Combat Training (BCT), followed by Advanced Individual Training (AIT), with the exceptions of cavalry scouts, infantry, armor, combat engineers and military police recruits who go to One Station Unit Training (OSUT), which combines BCT and AIT. The Navy sends its recruits to Recruit Training and then to "A" schools to earn a rating. The Coast Guard's recruits attend basic training and follow with an "A" school to earn a rating.


While capability development is about enabling the military to perform its functions and roles in executing the defence policy, how personnel and their equipment are used in engaging the enemy, winning battles, successfully concluding campaigns, and eventually the war – is the responsibility of military operations. Military operations oversees the policy interpretation into military plans, allocation of capability to specific strategic, operational and tactical goals and objectives, change in posture of the armed forces, the interaction of Combat Arms, Combat Support Arms, and Combat Support Services during combat operations, defining of military missions and tasks during the conduct of combat, management of military prisoners and military civil affairs, and the military occupation of enemy territory, seizure of captured equipment, and maintenance of civil order in the territory under its responsibility. Throughout the combat operations process, and during the lulls in combat, combat military intelligence provides reporting on the status of plan completion, and its correlation with desired, expected and achieved satisfaction of policy fulfilment.
The next requirement comes as a fairly basic need for the military to identify possible threats it may be called upon to face. For this purpose, some of the commanding forces and other military, as well as often civilian personnel participate in identification of these threats. This is at once an organisation, a system and a process collectively called military intelligence (MI).
Later this became known as military science, and later still, would adopt the scientific method approach to the conduct of military operations under the influence of the Industrial Revolution thinking. In his seminal book On War, the Prussian Major-General and leading expert on modern military strategy, Carl von Clausewitz defined military strategy as 'the employment of battles to gain the end of war'.[34] According to Clausewitz:

The IRT model underlying ASVAB scoring is the three-parameter logistic (3PL) model. The 3PL model represents the probability that an examinee at a given level of ability will respond correctly to an individual item with given characteristics. Specifically, the item characteristics represented in the 3PL model are difficulty, discrimination (i.e., how well the item discriminates among examinees of differing levels of ability), and guessing (i.e., the likelihood that a very low ability examinee would respond correctly simply by guessing).
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