Hard Money Loans

With each project producing unique products or services, you may find it impossible to identify every unique task’s delays before they impact a deadline.  Skilled project managers often fail to deliver on time while some are able to stay on top of every moving task. The successful managers invest significant effort into creating, monitoring, and maintaining an accurate schedule.  Holding deliverables to an accurate schedule will reveal slippage before it’s too late.  It will also provide you with the comfort of knowing which tasks require your attention and when.

The acquisition of National City Bank of Ohio and its total assets of approximately 150 billion USD by PNC Bank of Pennsylvania triggered a cascade of events.  The acquisition resulted in one of the nation’s top five banks with 60,000 employees and 279 billion USD assets.  You can only imagine the enormity of decommissioning millions of lines of code and moving billions of records over a 23 month integration.  This required many simultaneous projects all dependant on each other to be completed on time.  To prevent one task on a critical path of any project impacting all projects, billions of investments, and thousands of customers, we used detailed scheduling techniques to plan and manage these projects and their critical paths.

There are several scheduling techniques that will show task dependencies, the duration of each task, when each task should start and finish, and the latest each task may finish before affecting the project.  A schedule network analysis can help you transform your task list into a visual representation, or network diagram of your tasks and their relationships.  A common network analysis is the Precedence Diagramming Method, which uses nodes and arrows to represent tasks and dependencies. Microsoft Project will allow you to create your diagram by adding tasks from your list or Work Breakdown Structure and use arrows to show dependencies and sequence as shown in Diagram 1.

The following relationships for tasks are common to projects:

• Many tasks will have a Finish-to-Start relationship where the second task can only start after the first task has completed as in Diagram 1.
• Finish-to-Finish relationship where tasks can only finish after its predecessor finishes.
• Start-to-Start relationship where one tasks can only start after its predecessor has started. 
• Start-to-Finish relationship where completing one task may depend on the start of another task.

Be aware of the types of task relationships, but you will find the finish to start relationship most common. Within your most recent project plan , determining the soonest your first task can start. This is not the date you expect it to start but the optimistic start date.  This is the task’s Early Start (ES) date as shown in Diagram 2.  Calculate the task’s soonest finish date or Early Finish (EF) date by adding the task’s duration to the ES (ES + D = EF).

Assuming your second task has a Finish to Start relationship, it’s ES date is the same date as the first task’s EF date as shown in red in Diagram 3.

Frequently, a task may have multiple dependencies and can only start after two or more tasks have completed.  In this case, use the EF from the dependency which has the latest EF date for the next task as shown in Diagram 4.

Missing an ES or EF alerts you to the start of slippage, but you also need to know when slippage is affecting your project.  You need to know how late tasks can start and how late they can finish before they will effect the project.  To calculate the latest each task can start without affecting the project, work backwards from your last project task.  If you would like to finish this project as soon as possible, use the EF of your last task as the LF of this last task as shown in red in Diagram 5.  To calculate the last task’s LS, subtract the duration of the last task from the tasks LF.  Once you have dates for your last task, work backwards carrying the LS to the previous task’s LF as shown in Diagram 5. 

As you work backwards, you may have two LS to chose from as shown in red in Diagram 6.  To determine the LF for Task 1 in Diagram 6, you will need to choose between the LS from Task 2 and Task 3.  Always select the earliest LS date.  In Diagram 6, Task 1 may finish no later than 2/6/09 because Task 3 must start no later than 2/6/09. 

Now that you have a solid grasp on when work can and must begin and end, it’s important to focus on those tasks that may not slip at all.  If you subtract each task’s EF from its LF, you will have each task’s slack.  Tasks that have the same EF and LF will have zero slack and may not slip at all.  Once you have determined each tasks slack, follow the zero slack path from your first task to your last to find your critical path.  It’s important to isolate this critical sequence of tasks because it will affect the entire project if any one of the tasks in the sequence is delayed.  Diagram 6 shows a critical path of Tasks 1, 3 and 4.  Delays to this path will definitely impact the project.

 Conclusion

Without a formal schedule and details, such as ES and LS, you can not begin to determine which tasks can and can’t be delayed without affecting the overall project.  Without the insight of an ES, the project team is unaware that a task is in danger of being late before it even starts.  Additionally, keep a close eye on your zero slack tasks which make up your critical path and start all tasks no later than their LS or they will impact the project.

 This Precedence Diagramming Method is essential to accurately monitoring the progress of your projects. There are several additional scheduling tools that will assist in further refining and controlling your schedule.  The critical chain method is often used with much success.  Some of the basic critical chain method concepts include reducing each task’s estimated duration and adding a buffer, providing backup resources and time to your critical chain.  The critical chain method also employs leveling your resources by making sure the workload is evenly distributed.  Alternate methods include, when necessary, compressing your schedule using crashing or fast tracking.  Crashing focuses on allowing additional cost as a tradeoff to reducing the project duration.  Fast tracking schedules tasks to run in parallel where they were once scheduled to run sequentially.  These additional methods will enhance your ability to control your schedules, but gain proficiency with your precedence diagram before enlisting these additional methods.  For additional information, if you are a PMI member, you will find Joel Kohler’s article “Fast Tracking or Backtracking?” and Michelle Colodzin’s “The Five Secrets of Project Scheduling” helpful.

Zel Nadal, PMP is a Corporate Banking Application Tech Lead with PNC Bank in Columbus, Ohio. He has developed enterprise applications since 1994 for companies such as American Express, GTE, Microsoft, Gateway, and Eckerd. Since 1998 he has managed information technology projects for companies such as Geico, BASF, Ohio Department of Health, and National City Bank.

Coauthor Preeti Kadu, PMP is a Corporate Banking Application Support Member with PNC Bank in Columbus, Ohio. She has managed many information technology projects for the company TCS.

Article Source:http://www.articlesbase.com/project-management-articles/the-importance-of-knowing-your-critical-path-1320876.html