Preconstruction can be defined as a service provided by a general contractor which produces objective data vital in making decisions that drive a projects financial viability. Common elements of preconstruction include budgeting, utility coordination, and cost reduction.
Integrated Project Delivery (IPD) takes that process and brings it to another level as the American Institute of Architects explains in "Integrated Project Delivery: A Guide":
To this basis, AIA emphasizes repeatedly that success relies upon “highly effective collaboration.” This may mean team members working outside their comfort zones: contractors who sketch details, architects who are proactive in value engineering and cost reduction, and owners that communicate clear budget goals. It can also mean expanding the team to include others such as building managers and maintenance staff, recognizing that their input can lead to a better project.