purposes of scheduling
Schedules cannot be 1:1 scale models of the construction process. If approximations between the scheduling model and the job are to be made, the most important question is “Why Have a Plan?” The answer to this question will depend on the questions you want to answer with the schedule. Here are some of the questions that the schedule can answer:
can we meet minimum requirements?
The most common reason for the use of schedules today is to meet the owner’s requirements to provide a monthly schedule update. In this case, schedules are typically created by off-site scheduling consultants who never discuss the project with the contractor or subcontractors. After the submission of the initial schedule, it is updated monthly to identify activities’ percentage complete. Such schedules may, or may not, need to be “cost-loaded.” Depending on the nature of the project and the experience of the project team such a minimum schedule may be sufficient. The problem is that one never really knows what is going to happen on the construction site. As the roulette spinner says, “You place your bets; You take your chances.”
is the project on-schedule?
Some owners require “earned value” analysis of their schedules. Earned Value analysis requires that the schedule track both the time and cost completion of each activity. First this means that the activities in the schedule updates must reflect those tasks that are actually taking place on the job site. Second, it means that each activity is required to report two values: Percent Cost Completion, and Remaining Duration.
Separating cost from time allows activities that have large up-front costs for equipment to correctly accrue costs. The day after delivery of a generator the “Install Generator” may have, for example, a Percent Cost Complete of 75% and a remaining duration unchanged from the original duration.
Another way that earned value analysis can help the team understand what is a happening on the project is to identify when work is falling behind schedule. Lets take the case of an activity that uses the same amount of resources each day, say wall painting. For such activities we could expect that if 75% of the value of the work has been earned, then the time required to complete the activity would be about 25% of its original duration. If however the owner has paid for 75% of the value of the work had been paid, but the task would require 75% of the original duration to complete, then the activity is in trouble.
who should be on-site today?
On complex projects, one of the most difficult coordination efforts is to ensure that subcontracting crews arrive at the job site to complete their work in an efficient sequence with other workers. One contractor out of step results in rework. The coordination required is not a technology problem it is a communication problem. The communication can, however, be made more clear through the use of schedules.
If schedules specifically identify subcontractor activities, then the timing for the arrival, scope of work, and departure of subcontractor crews can be clearly described to the whole team. Using the schedule as a communication vehicle may help decrease miscommunications. If there are delays or scheduling conflicts, then the impacts of these delays on following contractor and/or subcontractor activities may be clearly identified.
what happens if?
If the baseline schedule accurately reflects the way that the prime and subcontractors plan to do the work, and that the schedule is updated as the project goes along, then the schedule can be used to evaluate what would happen if changes are introduced to the plan. Schedule changes will directly add or remove specific activities and may also impact other activities ore the overall completion of the schedule
what happens now?
Someone should write a book entitled "Why bad things happen to good projects." As it turns out, all of us have war-stories that could be included in these web pages. A schedule that accurately reflects the changes during the project will allow the entire team to quickly understand the context in which a problem occurred and the impact of that problem on other activities and the project completion.
what happened then?
I have nothing against lawyers; however, requiring expensive lawyers to recreate the project at the time of the problem by going back through daily reports, progress photos, etc… decreases the resources we all have to do productive work. Having an up-to-date schedule when a problem occurs will assist the project team to more rapidly resolve the issue and impacts then get on with the work.
okay, so how will the CPM tutor help?
The CPM tutor will assist you to understand the tools, techniques, and lessons learned needed to answer the questions above!