9.1: Schedule Compression

Notes

Video 9.2: Fast Tracking

Video 9.3: Laddering

Fill in the missing task names below after watching the video on Laddering.

Diagram of the laddering process with blank spaces for missing step names.

Assuming the time for all tasks are 1 week (Dig Ditch A, Dig Ditch B, Cover Ditch A, etc) and if laddering was not used, the project would take 9 weeks. With laddering, how long would it take?

Video 9.4: Crashing a Project


Check Your Knowledge

Questions: Reducing Project Duration

Exercise 1

You are given the following data about project tasks, network, and crash times/costs. Calculate the cost of the project at all time durations until you can no longer crash the project. All times are in days.

ID Direct Costs Slope Maximum Crash Time
Normal Crash
Time Cost Time Cost
A 5 $500 4 $600 $100 1
B 10 $1,200 6 $2,000 $200 4
C 13 $3,600 11 $4,800 $600 2
D 13 $300 11 $600 $150 2
E 5 $1,000 4 $1,400 $400 1
F 10 $2,400 8 $5,400 $1,500 2
G 5 $700 5 $700 $0 0

 

Project network diagram: A leads to B or C. B leads to D, which leads to G. C leads to E, which leads to F, which leads to G.

Exercise 1.B: Initial Network

Calculate the critical path(s) and the direct costs of this project:

The same project network diagram with blank spaces.

Critical Path 1:
Duration:
Critical Path 2:
Duration:
Project Duration:
Total Direct Costs:

Exercise 1.C: Crashing

If possible, calculate the critical path(s) and the costs of crashing this project by 1 day:

Critical Path 1:
Duration:
Critical Path 2:
Duration:
Project Duration:
Normal Duration Direct Costs:
Additional Costs of Crashing:
Total Cost at this time period:

Repeat these calculations until the project can no longer be crashed.

Exercise 1.D: Total Costs

Record the direct costs that you calculated at each duration in the table below. Calculate the total project costs (figuring in the $500 per day incentive to finish early) at the various time periods.

Initial Dur -1 -2 -3 -4 -5 -6 -7
Project Duration
Total Direct Costs
Incentives ($500 per day that project is delivered early)
TOTAL COSTS

What is the optimum time period in terms of total cost?


Exercise 2

You are given the following data about the project tasks, network, and crash times/costs.
Calculate the cost of the project at all time durations until you can no longer crash the project.

ID Direct costs Slope Maximum Crash Time
Normal Crash
Time Cost Time Cost
A 10 $5,000 10 $5,000 $0 0
B 12 $1,200 11 $1,300 $100 1
C 11 $3,600 9 $4,800 $600 2
D 5 $300 4 $600 $300 1
E 8 $1,000 6 $2,000 $500 2
F 9 $2,400 7 $5,400 $1,500 2
G 8 $700 7 $1,000 $300 1

A project network diagram: A and B lead to C. C leads to D, E, or F. D, E, and F all lead to G.

Exercise 2.B: Initial Network

Calculate the critical path(s) and the direct costs of this project:

Critical Path(s):
Project Duration:
Total Direct Costs:

 

The same project network diagram with blank spaces.

Exercise 2.C: Crashing

If possible, calculate the critical path(s) and the costs of crashing this project by 1 day:

Critical Path(s):
Project Duration:
Normal Duration Direct Costs:
Additional Costs of Crashing:
Total Cost at this time period:

Repeat these calculations until the project can no longer be crashed.

Exercise 2.D: Total Costs

Record the direct costs that you calculated at each duration in the table below. Calculate the total project costs (figuring in indirect costs) at the various time periods.

Initial Dur -1 -2 -3 -4 -5 -6 -7
Project Duration
Total Direct Costs
Indirect Costs $3,000 $2,500 $2,000 $1,500 $1,000 $500 $250 $0
TOTAL COSTS

What is the optimum time period in terms of total cost?

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