Two characteristic manpower flow under different recruitment policies

Different basic stock equations are obtained for a two-characteristic manpower flow, under different recruitment policies. The first set of equations is derived for the situation when for each state, a fixed proportion of stocks are recruited for each time point. The second set of equations is applicable to the case when all vacancies are anticipated and filled up with a fixed proportion of the vacancies being recruited. Finally, the recruitment policy is discussed when the grade sizes expand geometrically.