The graphic shown above is illustrating that the Scope of a project can be expressed as the sum or collaborative interaction of the its Time, Cost, and Quality. I would expand that definition and restate it as the Total Project equals the sum or collaborative interaction of the Scope, Quality, Time, and Cost. This relationship is often studied in business school on the topic of project management and is, actually, quite simple. The problem is that accepting its outcome is not always that easy. There are times in a project when difficult decisions must be made. And understanding this relationship early on in the project (preferably before it begins) helps in making these decisions. Failing to understand and accept this concept can bring a project to a standstill.
Definitions:
Scope = What is to be done or accomplished. For example, add a master suite, remodel a kitchen, or build a new house.
Quality = Most often this refers to the level of finishes. But it also refers to the building systems: For example, granite versus laminate counter tops, hardwood flooring versus carpet. Examples of building systems include roof, siding, heating and air conditioning, insulation, and many others.
Time = The schedule. How much time it will take to design and build your project. It also includes the sequence of each step in the process. Complex projects take more time to plan and construct than simple projects.
Cost = The budget. How much money (or resources) will the project consume. Labor and material make up a large part of the project. But the time spent planning and managing the project also consume precious resources. There are also many fees to be paid to regulating agencies that are required but not productive.
As much as we all would like the design and construction process to be predictable, stable, and certain, it is actually somewhat fluid and dynamic. While there are many external factors (state and local building and zoning codes, availability of material and labor, weather, site conditions, pre-existing conditions, neighbors, relatives, and regulating agency personnel) affecting the project, there are also many internal factors (design team, construction team, and owners) as well.
No one likes variability or volatility in their project. Neither do I. But the confluence and shear number of variables that exist in a project simply require you to expect this and plan for it. The simple answer to all issues that present themselves is to commit more resources. While it is the simple answer, most clients do not have unlimited resources. And even when more resources can be dedicated to an issue, it is still prudent to review the situation to understand all the alternatives for resolution.
The key to understanding this principle is the relationship between Scope, Time, Cost, and Quality. At the beginning of every project, the scope is defined, the level of quality and finishes are established, and the budget and schedule are set. During the course of design and construction, changes present themselves.
The four variables are directly related. The relationship between these variables is such that if you change one of the variables, only two of the others can be held constant. The remaining other (fourth) variable must change. And in reality, many of the variables change in response to a change in one variable.
While this may sound like a science experiment or a complex mathematical equation, it is really quite straight forward. Here are a few examples to illustrate how these variables interrelate:
These scenarios assume that the scope is defined, level of finish and quality has been decided, a schedule is established, and, finally, the budget for the project is set.
Scenario 1: Scope expansion - Example: A bathroom is added to the scope of the project.
This impacts the project in two ways: first it will add cost to the project. Second, it will increase the amount of work overall, which will lengthen the schedule.
This can most simply be resolved by increasing the budget to cover the cost of the labor and materials for the added bathroom. To keep the project on schedule, more resources (increasing cost further) will likely have to added, as well, to complete the project in the original time frame.
However, if the budget is set and cannot be increased, the level of quality on the project may be reduced. By spending less on other parts of the project, this may offset the added cost of the increased scope.
Alternatively, the scope of the project could be reduced elsewhere to keep the project on schedule and within budget. However, it is important to note that many materials have lead times for procurement and depending on when the scope expansion is requested, the availability of material (and sometimes labor) may still impact the schedule (lengthening).
Scenario 2: Increase the level of finishes or quality - Example: Change the originally specified flooring from carpet to hardwood.
This material change will add cost to the project.
Here again the simplest way to cover this increase in level of quality or finish is to simply increase the budget.
Always keep in mind that changes will, depending on when requested, very likely affect the schedule. If the upgrade were planned before the flooring was installed, it may not affect the schedule. However, if the change was requested after the planned material was already purchased and right before its planned installation, this may greatly affect the schedule (and possibly add cost as well).
Alternatively, the scope could be reduced. If, for example, this project had a landscape portion, remove this part of the project, or at least delay it, and plan it for another, later, phase to be completed in the future. This reduction in scope allows more resources to be committed to the desired changes.
Another possibility, this change may be covered by reducing the level of quality elsewhere in the project. For example, to enable the upgrade on the flooring, the counter top in the laundry room maybe downgraded from granite to a laminate.
Scenario 3: Schedule change - Example: Anticipated completion date is accelerated.
This schedule change reduces the amount of time available to complete the project.
To complete the project sooner than initially planned will require additional labor resources. This will likely add cost to the project, increasing the budget.
Depending on material availability, it may not be possibly to accelerate the schedule. If possible, materials will likely have to be expedited. Again, this increases cost (budget).
Accepting a lower level of finish or quality will often times allow for an accelerated project completion date. A higher level of finish is often associated with project complexity and takes longer to complete.
Lastly, reducing the scope of the project will enable the project to be completed faster. With less to do, the project will be completed in less time.
The above examples illustrate just a few of the many possibilities that can and do commonly occur during the course of a project. And each resolution listed is only one of many options available. These examples illustrate how complex and intertwined the various components are. Often, changes in one will affect at least one and, more likely, all the others.
A Project can be defined by its Scope, Quality, Schedule, and Budget. Changes often occur during both the design and construction phases of a project. When change presents itself during your project, understanding this inter-relationship will help you understand how the decisions you make impact your project.