Precedence Planning and Scheduling

Question 1

Precedence planning

Answer 1

Defining the logical sequence of the work packages

Question 2

Scheduling

Answer 2

Defining the temporal sequence of the work packages

Question 3

Dependencies

Answer 3

• technological
• organizational
• mandatory
• discretionary

Question 4

Milestone chart

Answer 4

• simple chart of most important events
• Purpose: rough planning, reporting

Question 5

Bar chart

Answer 5

• shows activities, start date, and end date (or duration)
• shows schedule against calendar time
• Purpose: planning, reporting, and progress tracking - dependencies must be known but are not visualized

Question 6

Activity network diagram

Answer 6

I. same as bar chart
II. shows dependencies between work packages and workflow
- used to calculate critical paths
- Purpose: detailed planning and progress tracking

1. Identify work packages
2. Identify dependencies between work packages
3. Estimate duration for each package
4. Create network
5. Calculate
   a) early start, early finish
   b) late start, late finish

Question 7

Precedence Relationships

Answer 7

1. Finish-to-Start dependency (FS)
   - WP2 may start only after WP1 has finished
2. Start-to-Start dependency (SS)
   - WP2 may start only after WP1 has started
3. Finish-to-Finish dependency (FF)
   - WP2 may finish only after WP1 has finished
4. Start-to-Finish dependency (SF)
   - WP2 may finish only after WP1 has started

Question 8

Computing a Schedule - Forward calculation

Answer 8

1. ES(start) = 0
2. EF(wp1) = ES(wp1) + duration(wp1)
3. ES(wp2) = max(EF(wp_n)), wp_n is predecessor of wp2

Question 9

Computing a Schedule - Backwards calculation

Answer 9

1. LF(end) = EF(end)
2. LS(wp2) = LF(wp2) - duration(wp2)
3. LF(wp1) = min(LS(wp_n)), wp_n is successor of wp1

Question 10

Total Float and Free Float

Answer 10

1. Total Float
   - Time that a work package may be delayed or extended from its early start without delaying the projectʼs finish date: Float = LS - EF or LS - ES
2. Free Float
   - Time that a work package can be delayed without delaying the early start of any immediately following work package
3. Interpretation
   - Float > 0: time is available
   - Float = 0: situation is critical

Question 11

Critical Path

Answer 11

1. Critical work package
   - Float = 0
   - often: ES = LS
2. Critical path
   - Path through the network consisting of only critical work packages
   - Sum of total float on a critical path is zero
   - At least one of the critical paths determines the shortest project duration
3. Critical path is important to…
   - identify schedule risks
   - focus progress control
   - shorten project duration

Question 12

Schedule Compression

Answer 12

1. Fast tracking to shorten critical path
   - Do activities in parallel instead of sequential
   - Consider discrete dependencies
2. Crashing the network
   - Costs and schedule tradeoffs are analyzed to determine how to obtain the greatest amount of compression
   - Allocation resources to critical path
   - Hiring additional resources
   - Bonus payments for early completion
   - Increase productivity by applying different technology
   ⇒ overtime and weekends should not be considered!