Considerable research during the last two decades has concentrated on aggregate production
planning, inventory control, and scheduling. Aggregate planning procedures, which have
been proposed for both manufacturing and service organizations, help determine monthly
(or quarterly) output, inventory and manpower aggregates. Inventory and scheduling
procedures, using the aggregate decisions as input, tend to focus on such short-term
decisions as (i) the sizing and timing of production (purchase) orders for specific items, (ii)
sequencing of individual jobs (orders), and (iii) short-term allocations of resources to
individual activities and operations. The total process of going from aggregate plans to more
detailed plans can be called disaggregation.
Disaggregation is an important issue in manufacturing as well as service organizations.
Depending upon the nature of the production system, disaggregation decisions in a
manufacturing organization may exist on one or more of the following three levels:
1. Given aggregate decisions on output and capacity, determine the timing and sizing of
specific final product production quantities over the time horizon (sometimes referred
to as a master schedule).
2. Given the timing and sizing of final product production quantities, determine the timing
and sizing of manufactured (or purchased) component quantities.
3. Given the timing and sizing of component quantities, determine the short-term
sequences and priorities of the jobs (orders) and the resource allocations to individual
operations.
The taxonomy shown on the left side of Figure 1 provides the framework with which the three
levels of disaggregation in manufacturing organizations.