1. I love the sound they make as they fly by.
Scheduling Work
I love deadlines.
I love the sound they make as they fly by.
-- Douglas Adams

2. Software Engineering : A Practitioner’s Approach by Pressman
Why is software late?
Under-Estimate of effort.
Unrealistic deadlines imposed by outsiders.
Changing requirements.
Risks that were not considered.
Technical problems that could not be foreseen.
Failure to recognized that the project is falling behind schedule and lack of action to correct the problem.
Software Engineering : A Practitioner’s Approach by Pressman

3. How to build a schedule:
Determine dependencies of activities found in WBS.
Use dependencies to build activity network diagram (eg PERT).
Determine critical path.
Map network to a timeline (eg Gantt Chart) using the effort estimates.
Use a software tool to help do this work.

4. Why Determine Dependencies?
Dependencies determine deadlines and when work can begin.
The WBS shows hierarchy, not dependency.
Planners must find all dependencies.
Surprises are very bad!

5. Dependency Types External Dependency Internal Dependency
Other projects
Stakeholders
Sub-Contractors
Internal Dependency
Audits (design, testing, documentation, …)
Sign-Offs at end of phase

6. Dependency Types FS - T2 cannot start until T1 is finished.
Start Finish
FS - T2 cannot start until T1 is finished.
coding must wait on design to be finished
SS - T1 and T2 must start at same time.
documentation and coding start together
FF - T1 and T2 finish at same time.
configuration management ends when coding is done

7. Dependency Types
Lag – T2 cannot start until a given amount of time after T1 is done.
Start on-site training one week after final demo to customer management group.
Soft – T2 should start after T1, but it is not completely essential that T1 be finished.
Populate the new database after the database has been built. If the new database is not completely finished we can still populate the few finished tables.

8. Activity Networks CPM – Critical Path Method
activities are graph nodes (circles)
single estimate for duration of tasks
PERT – Program Evaluation and Review Technique
activities are graph arcs (lines)
activity times are ranges and include probabilities

10. http://www. mckinnonsc. vic. edu

11. Example Activity Network – Activity on Node
1wks
2wks T5 T2
1wk
3wks
1wk
2wks
1wk T1 T4 T6 T8 T9
4wks T3
3wks T7
Questions:
Minimum time to complete the project?
Critical Path?
Earliest start time, latest start, earliest finish, latest finish?
For T2  es=2ndwk ls=4thwk ef=3rdwk lf=5thwk

12. Resulting Gantt Chart 1 2 3 4 5 6 7 8 9 10 11 12 13 14 T1 T2 T3 T4 T5

13. Next Time… Making Good PERT charts Managing Uncertainty
Resource Leveling
Matching to the Calendar and External Resources
Correcting Misinterpretations
Managing Uncertainty
Automated Tools