If you are planning a construction project, whether it's a new office complex or a home addition there is a good chance you will not be the one doing the actual design or construction. Sure you'll have input, it is your project after all, but you hire professionals because they have the expertise you lack. The majority of construction projects follow the "design-bid-build" formula. That is you hire an architect to design your building or addition, use the drawings to secure your building permit, solicit bids from a number of contractors, award the project, usually to the lowest bidder, and have it built. Using this process each step is distinctly its own and there is very little, if any, interaction between the design and construction teams, both of which you hired. You may in fact find that the architect and the contractor bad mouth each other. If this is the case you run the risk that what was designed and what gets built may not quite align.
With the design-bid-build process decisions are largely made based solely on cost. A more holistic, some would say better, way of making these decisions is through integrated design. Integrated design is just what it sounds like, integrated, joined together. The entire project team, both design and construction teams, is assembled at the start and works together for the duration of the project. That means you don't have a set of drawings to show a contractor before s/he's hired, you have to interview contractors and select one, not based on cost but on the value they bring to the table. In this sense you are using similar criteria to hire a contractor that you would to hire an architect or other design professional.
While the owner will be ultimate decision maker regarding the project s/he can make more informed decisions with input from the design and construction teams and set overall goals for the project in terms of scope, performance, and cost. By facilitating a dialog between the design and construction teams early in the project each team member is able to share their thoughts and concerns on how to reach those goals. The construction team will be able to assess how design decisions will affect construction and solutions to potential problems can be discussed while still in the design phase. Additionally, the design team will be able to anticipate construction activities and adjust the design accordingly. Everyone knows it's a lot easier, and cheaper, to change the design when it's still ink on paper than when they are brick and mortar.
When the construction team is included in the design process they have a complete understanding of the design and there is buy-in. The construction team, by being a part of the design phase and providing input on design decisions, has effectively endorsed the design. After taking part in this process the construction team will work its hardest to ensure a successful project. Additionally, by being a part of the design phase the construction team will be able to more accurately price the job. Thorough discussions on how design decisions affect construction should lead to a full understanding of the project. This should reduce the amount of change orders and help keep the project on schedule meaning the owner can be more confidant in the prices submitted by the construction team.
Each phase of the project will move more smoothly with continued communication. When construction starts the construction team will have an intimate knowledge of the design and will know the reasoning behind each decision. If additional changes are required in the field it is important that the entire team understand the full implication of all decisions, which is more likely with integrated design. By discussing all issues that arise after the start of construction with the entire team solutions can be reached that everyone agrees with and will help meet the projects goals.
With a full understanding the design throughout the project, continued communication, and collective problem solving the project team should be able to deliver a building that all those involved are proud of. By making decisions based on value, not cost, and with the entire project team, the final result of integrated design is a quality building that meets the owners goals while working towards a better way of building.