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TOOLS & TIPS to Monitor and Control
The Time of a project answers the question "When" will you actually do the project work. To Monitor Time, you will look to see if the things are being done in the right sequence and at the right times. To Control Time you will make the necessary corrections to get "back on plan" as required. Occasionally you might need to change the plan to preserve the project end date. Only after trying all possible remedies, or after you have been given significant approved scope change, should you consider requesting a change to the end date of your project schedule
While it might not be possible to monitor everything, do pay special attention to activities that are on the Critical Path.
Critical Path: The sequence of Activities that represents the longest path through a project, which determines the shortest possible duration of the project.
If you missed the CPM tutorial, you can click the blue button at the bottom of this page.
Click on any photo to get to a project step
How to MONITOR (INSPECT) TIME:
Simply follow these steps:
Find today's date at the top of the page. Say today is start of Day 8.
Draw a line (yellow) vertically down from today's date to the bottom of the page.
All activities to the left of the yellow line should be done.
All activities to the right of the yellow line should be up-coming, or in progress.
Use a bar (green) to indicate the amount of progress
In our example, above:
Activity 3.3.1 is done
Activity 3.2.2 is 1/5 (=4/20) done. That represents 4 days' worth of work on the plan. It should be 7/20 done by now. It is running behind schedule by 3 days.
Activity 3.2.1 is 9/10 done. That represents 9 days' worth of work on the plan. It is running 2 days ahead of schedule.
Activity 3.1.3 is 3/5 done. That represents 3 days' worth of work on the plan. It should be finished by now. It is running late.
Activity 3.1.2 is 6/15 done. It should 7/15 done by now. It is running behind schedule by one day.
Activity 3.1.1 is done
Activity 2.0 has not started
Only activities on the Critical Path can affect the project completion date. Finishing a non-critical-path activity early does not shorten the overall project duration. A non-critical-path activity might run late without affecting the overall project duration (click the blue to review the section on floats).
Activity 3.2.2 is in trouble and will affect the project end date. This requires corrective action.
Activities 3.1.3 and 3.1.2 should be watched but are not yet affecting the project end date.
CONCLUSION: The project is at risk of taking 3 days longer, determined by looking at the Critical Path activity (3.2.2). The activity which is ahead of schedule (3.2.1) does not advance the finish date, as it is not on the Critical Path.
How to CONTROL (CORRECT) TIME:
In our project we need to find a way to correct the Time problem of likely finishing 3 days late. We need to get the schedule "back on track". Two effective tools for schedule compression can be used to correct this Time problem. They are:
Fast Tracking and
We will look at each of these in turn.
Fast Tracking is the technique of running two consecutive Activities at (or partially at) the same time. You might have considered fast tracking as part of your plan, but we will look again as a method to correct our 3 day Time problem. There is no change of Scope. For example the top coat of paint follows the primer; but you might be able to start top coating one room before the whole house is primed.
Here is how it works:
1. Look again at your CPM diagram. We will use the "Plan Parade" project shown here:
1. Find an activity on the Critical Path which can be started before all of
its predecessor (coming before) activities are done. In this project we
realized that we can start to assemble documents about first aid
supplies and about permits, without waiting for the security and first aid
staff to be organized. In other words we can assemble documents for
people separately from documents for first aid supplies and permits.
It is much simpler to remove the milestone activities from your diagram where fast tracking will occur. Below is exactly the same Critical Path diagram now with two of the milestones removed.
The diagram below illustrates Steps 2, 3, 4, and 5.
2. Split the activity, Assemble All Documents into two activities; being
Assemble People Documents and Assemble Other Documents.
3. Feeding into the activity Assemble People Documents are the activities
Organize Security and First Aid Staff.Draw this.
4. Likewise feeding into the activity Assemble Other Documents are the
activities First Aid Supplies and Get Permits. Draw this.
5. Recalculate the CPM diagram Starts and Finishes.
In the fast tracked critical path diagram, above, we can note a few important observations and comments:
The total project duration has been reduced to 20 days from the original 25 days; a saving of 5 days.
Assemble Documents will still take 5 days, but is now split between Assemble People Documents (3 days) and Assemble Other Documents (2 days), allowing these two to run consecutively.
Likewise, Arrange First Aid will still take 20 days, but is now split between First Aid Staff (17 days) and First Aid Supplies (3 days) allowing these two to run consecutively.
A part of First Aid is still on the Critical Path. It is the people (staff) part of First Aid. Also, a part of Assemble Documents is still on the Critical Path. It is the people part.
The path which includes First Aid Supplies, Get Permits, and Assemble Other Documents is called the "Fast Track". This is because we can start to assemble documents about first aid supplies and about permits, without waiting for the security and first aid staff to be organized.
Fast tracking only shortens project duration when applied to the Critical Path.
The floats of many other activities are affected, generally shortened, after Fast Tracking
In the example above the split of Arrange First Aid was: 17 days for First Aid Staff and 3 days for First Aid Supplies. Suppose the split was different, for example 10 days for First Aid Staff and 10 days for First Aid Supplies. The resulting CPM diagram would then be:
In this case, we have shortened up the Critical Path so much that some other path has become the longest (Critical) one, and the Arrange Bands activity will now require much more attention than before. Watch out for this when fast tracking!
Here are other precautions about Fast Tracking:
Look only at Critical Activities as candidates for Fast Tracking. Project duration will not be shortened by Fast Tracking non-Critical Activities.
Make sure the resources are available to support the new Critical Path diagram. Generally, people will be required to start their activities sooner.
The Risk of under-achieving quality and subsequent re-work (with added Cost) is increased because we do not get to see the first Activity fully completed before starting the second one.
Fast Tracking does not necessarily cost you anything, but it is risky. Fast Tracking gone wrong can end up adding Time to the project duration, "Haste makes waste!"
The floats of many other activities are affected, generally shortened, after Fast Tracking.
Crashing is the technique of shortening the schedule duration by adding more resources, usually money, to Critical Path Activities. There is no change to Scope. I like to think of it as "throwing money at the problem".
Some typical examples of Crashing include:
paying people overtime,
using faster but more expensive freight,
employing a faster but more expensive worker,
using a faster but more expensive machine.
Although Crashing can be applied to the original planned schedule, it often follows Fast Tracking as a means of correcting Time. Since we know Crashing will cost something, we first try to find our time saving by Fast Tracking. For this Crashing exercise, we will start with our Fast Tracked CPM diagram, shown again, below.
For this exercise, assume we need to shorten the schedule to 18 days, a saving of 2 days.
1. Update the original planned Activity List to reflect the Fast Tracked schedule. This is shown directly above.
2. Add columns to the Activity List for:
Days Saved. Possible saving opportunities
Cost for time saved. Cost to exercise those time savings
Cost/Benefit (the calculated ratio)
The resulting Activity table, (with some columns hidden) is shown below. We call this a Crash Table.
3. Look only at critical activities for possible crash candidates; in our case
Assemble People Documents and First Aid-Staff. (Non-critical activities will
not compress the schedule)
4. Insert the number of days that can be saved, and the cost for those savings.
5. Calculate the cost/benefit ratios.
6. Select the activity to be crashed, usually that with the lowest cost/benefit
In our example we will choose to crash Assemble People Documents, because:
It is on the Critical path
The cost/benefit is lowest at $25.00 per day saved.
It provides sufficient schedule compression for our needs.
Final points about Crashing:
Any amount of time you can shorten an Activity on the critical path will shorten the overall project duration by the same amount of time
Look only at Critical Activities as candidates for Crashing. The activity Organize Security has the lowest cost/benefit ratio but it will not shorten project duration as it is not on the Critical path.
Not every Critical Activity will have an opportunity for Crashing
Crashing will cost you something. It is not free. Be sure you actually get the benefit you pay for.
The floats of many other activities are affected, generally shortened, after Crashing.
Below is the final CPM diagram after Crashing.
For a review on making CPM diagrams, click the blue button at the bottom of this page
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