What are the minimum recommended general scheduling guidelines for efficient schedule management?
A lot of thought and effort goes into the creation of a project schedule. The project manager must consider many things, and it is not always easy to keep the most important items in focus. Therefore a short list of bare minimum schedule requirements helps project managers keep what matters most front and center like critical gages on a control panel.
This article reviews a short list of the most important and fundamental general scheduling guidelines to support efficient schedule management.
Activity
- Activity Names – Activities represent tasks for work packages, and should have unique names represented by a verb-noun combination, e.g. create drawings, build prototype, inspect piping.
- Minimize abbreviations – Abbreviations breed confusion, so keep them to a minimum, and include an abbreviations list.
- Uniform naming structure – standardize conventions for naming activity descriptions.
Activity Relationship
- Relationships – Make certain all activities are logically linked. The start activity is the only activity without a predecessor and the finish activity is the only activity without a successor. Linked activities support a continuous critical path or longest path through the network.
- Relationship types – There are four relationship types FS, SS, FF, and SF. Limit and explain the usage of SF relationships. In an effort to base effort or progress on known scopes of work 90% of all activities should be FS.
- Lead (Negative Lags) – Most scheduling guidelines prohibit the use of leads or negative lags, because at best leads are confusing and at worst they may violate network logic. They also may distort total float and the critical path. Do not use leads. But if you insist then be aware that many government agencies prohibit the use of leads, so check your customer requirements package.
- Lag (Positive Lags) – Some guidelines only allow contractually defined positive lags. This requirement severely restricts their usage. Wide adoption of positive lags is discouraged because lags, even positive lags, are not well documented. The delay, appears on the Gantt chart as a simple line.But what is the reason for the lag delay? The less informed stakeholder will not know, unless there is a note of explanation. Some specifications say FS relationships should not have any lag, because they appear as time gaps on the Gantt chart. Positive lag customized FS relationships therefore breed confusion, and should be avoided.
Constraints
- Hard Constraints – Hard constraints should be avoided because they may violate network logic. Some guidelines like the Defense Contract Management Agency’s (DCMA) 14-Point assessment allows up to 5% of constraints to be hard. The 14-Point Assessment, perhaps, is not judicious enough in this assessment. Schedulers are recommended therefore to avoid the use of hard constraints in their schedules.
- Constrained Milestones – Constrained milestones, e.g. modeling the delivery of raw materials and/or equipment, are acceptable. Meetings may also be defined with a constraint. Some guidelines say only constraints written in the contract are acceptable. You may want to constrain the contractually agreed upon date for submitting deliverables.Constraints that do not fragment the longest path are acceptable, but broad application of constraints is discouraged. Insertion of constraints should be a rarity because they make the schedule static, i.e. unresponsive to schedule changes and progress updates.
Miscellaneous
- High Float – High float is every project manager’s dream. It’s like a built in safety margin. It says your activity may delay and still not negatively impact the completion date of the project. But too much high float may be indicative of poor logic, perhaps, a missing or weak successor relationship. It’s like your activity is not well tied into the schedule and is left dangling, perhaps, completely on its own. Activities that have 44 working days or more total float are suspect and may require review.A good rule is that not more than 5% of your schedule’s total activities should have high float. If your schedule exceeds this threshold you will need to examine each activity with high float. Take a step back to gain a new perspective on your schedule. Most likely there is an activity that makes for a successor that can logically tie your dangling activity back into the project schedule.
- High Duration – High duration tasks have duration equal to or greater than 44-days. This is approximately 2-months. Projects are typically updated on a monthly basis. You would normally expect a progressing activity to either start or finish during this normal status cycle, but not be in a seemingly continuous in-progress state due to its long duration. So high duration tasks make it harder to get visibility into the project schedule status and progress. Quality schedules will have no more than 5% of total schedule activities as high duration.
Summary
So there is your dashboard control panel of items to keep in plain view for efficient schedule management. Additionally, schedulers would do well to review the Naval Facilities Command (NAVFAC) Integrated Project Schedule (IPS) schedule checklist and the Defense Contract Management Agency’s 14-Point Assessment.
Project managers that have a good handle on general scheduling guidelines have a significantly better opportunity for successful schedule management. These general scheduling guidelines do not represent a pass/fail criteria, but rather are the impetus for further schedule review, discussion, and, hopefully, consensus.
For more guidance in scheduling refer to “Construction Scheduling with Primavera P6” by Jongpil Nam.