This discussion will be confined to the critical path and the methods for salvaging a project schedule that is slipping. I confine the discussion because constructing, tracking, and reporting on a project schedule are straight-forward activities - even algorithmic. The advent of software tools lends credence to this view.
It is more important to focus attention on triage activities when a project schedule has slipped. This process is heuristic and success depends upon the project manager's experience and intuition to construct a solution. So given that a project schedule has changed sufficiently to require fixing, the project manager will perform Critical Path Analysis.
Analyzing the Schedule
Critical Path Analysis is the process of reviewing one of the sequential paths through the schedule to see if there is an opportunity to make that path shorter. The Critical Path is the longest duration path through the schedule and defines the Completion Date of the project. Therefore, only the critical path is analyzed because it is the one path to which changes will directly affect the Completion Date.
When a project schedule has slipped and will not make the target date the Project Manager must review the schedule for opportunities to get the project back on-track. There are two categories of options for fixing a slipped schedule. One is Schedule Compression, the other is Due Date Change.
Fixing the Schedule
The category of Schedule Compression includes four activities to get the schedule back on track to meet the previously set Completion Date. The first activity is Concurrency Finding. This is the process of reviewing all of the sequential activities (on the critical path) to determine if any may be converted to some form of concurrency. It may be that portions of otherwise sequential tasks may be partitioned and then performed concurrently and thus be able to shorten the critical path.
The second is Staff Addition to selected activities to distribute the work and complete it faster. This activity must be used with caution. Research has shown that adding staff to a delayed schedule will in-fact make the project slower. Therefore, the project manager must be judicious in adding staff. Instead of adding multiple developers to a team, one person may be added and moves between activities assisting in very specific ways.
The third activity is using some of the Management Reserve time that was included in the schedule when it was first set. Reserve time of 5-10% is generally included in the schedule for unpredictable contingencies. The reserve time are extra days in the schedule that help absorb schedule slippages. By allocating reserve time to the slippage, the completion date remains on track.
The fourth and final activity of the Schedule Compression option is Product Reduction. This means the product is reduced by one or more features so that those remaining may be completed and delivered on-time. This will require negotiations with the customer as to the feasibility and acceptability of this option. In addition, the customer must make the decision as to which features to retain and which features to remove form the product.
The Product Reduction option is more prevalent in the Extreme Programming (XP) method than in the Traditional Project Management method. XP is an iterative development method with faster, shorter intervals between completion dates. There is more flexibility in reducing the product scope for a particular completion date because it can be included in a subsequent iteration.
The second due date salvage category I refer to as Due Date Change. As its name implies, the project manager changes the due date of the project to one that is attainable by the current status of the schedule. There are two steps to be performed to complete this option.
First, the project manager must calculate the cost of a due date change. The most obvious cost may be a fine or penalty payment charged by the customer for a due date extension. This cost must be compared to the costs associated in the Schedule Compression options such as increasing the staff. If it is cost effective to proceed with this option, then the project manager continues with step two.
Second, the project manager re-negotiates the due date given certain cost and schedule constraints.
In the investment field, I have made such decisions. A targeted closing date for a loan can be delayed and there are financial costs for both the lender and the borrower. If the delay is due to the borrower's failure to complete specific tasks, then as lender I can assess a per diem charge for each day of delay. If the failure is on the part of the lender, then we can extend the closing date and by so doing lose interest on the funds we have committed but sequestered. The funds do not earn interest when committed to a loan, but remain un-disbursed because the loan has not closed. The lender may also horse-trade the allocation of fees and other closing costs to the lender to compensate the borrower.
Reviewing a slipping schedule in order to get it back on track requires experience and intuition on the part of the project manager. There are several activities that can be used alone or in combination to fix the schedule. These include Concurrency Finding, Staff Addition, Management Reserve, Product Reduction, and Due Date Change. The first four belong to the general category of Schedule Compression wherein the original completion date is maintained and the schedule is adjusted to meet that date. The latter activity, Due Date Change, is the category of changing the completion date and analyzes the costs of such a change.
- Beck, Kent and Martin Fowler, Planning Extreme Programming, Boston, MA: Addison-Wesley, 2001.
- Project Management Institute, A Guide to the Project Management Body of Knowledge, Newton Square, PA: Project Management Institute, 1996.
- Rakos, John J., Software Project Management for Small to Medium Sized Projects. Englewood Cliffs, N: Prentice Hall, 1990.
- Wysocki, Robert, Effective Project Management 3rd ed., Indianapolis, IN: Wiley Publishing, 2003.