The first step in developing a schedule is the listing of the Tasks that must take place for the project to complete. An important consideration in preparing the list of Tasks is the Level of Detail that the schedule requires in order to be effective. The purpose of the schedule, and its intended audience, may dictate anything from a high-level summary of the work to be performed, to a specific work plan for the project.
With your desired level of detail in mind, you will begin listing the Tasks that will be included in the schedule. You can draw on many resources to develop your Task list, including previous schedules, project specifications, and input from subcontractors or other participants in the project. You can also create the list of tasks by working through the project mentally or on paper, and taking note of each Task to be performed. The task list does no have to be 100% complete before you move on, but the more accurate your list is in the beginning, the less time you will spend revising it later.
After a task is identified, you must also define the Duration of the task, or the amount of time you expect the performance of the task to require. These are most commonly defined in days, and specifically in work days, which may differ from calendar days if there are days where work is not performed in your schedule (Weekends, Holidays, etc).
Developing good estimates for task durations is one of the more challenging aspects of creating an accurate schedule, and you may need to utilize many resources to arrive at a reasonable estimate. Your own experience, industry guidelines, publications, and input from subcontractors or other participants will prove useful in getting the best estimates. A common approach to calculating durations is to determine a total quantity of items to be installed, manufactured, constructed, etc. Once this total quantity is known, a quantity per hour, week, day, and so on can be identified, and the total divided by this number. This will provide you with a total duration that is reasonable and based on sound information. Not every task is quantifiable this way, but many tasks have some sort of quantity that can be isolated for estimating purposes.
Example Task List - Making a Sandwich:
- Select Bread
- Select Meat
- Select Condiments
- Select Cheese
- Slice the Bread
- Place Bottom Slice of Bread on Work Surface
- Apply and Spread Condiments
- Apply Meat
- Slice Cheese
- Apply Cheese
- Place Top Slice of Bread on Sandwich
- Cut sandwich in half
Example Duration Calculation - Building a Fence:
- The length of the fence to be installed is 120 feet.
- The driving factor in construction of the fence is the installation of fenceposts, which are spaced 8 feet apart.
- It takes 20 minutes to install a single fencepost, so fenceposts can be installed at a rate of 3 per hour.
120 feet of fencing with 8 Feet between each fencepost requires 16 Fenceposts. 16 Fenceposts at 3 Fenceposts per hour is 5.3 hours for the installation of all fenceposts. Thus, the duration for the task of fencepost installation is 5.3 hours. If you are scheduling in hours, this task would be rounded up to 6 hours. If scheduling in days, the task would have a duration of 1 day.