PREV: Scope
UP NEXT: Cost Management
The knowledge area of Project Time Management consists of the following processes -
Time Management Processes
| Process | Project Phase | Key Deliverables |
| Plan Schedule Management | Planning | |
| Define Activities | Planning | Activity List, Milestone list |
| Sequence Activities | Planning | Project Schedule network diagrams |
| Estimate Activity Resources | Planning | Activity resource requirements,
Resource breakdown structure |
| Estimate Activity Durations | Planning | Activity duration estimates |
| Develop Schedule | Planning | Project Schedule |
| Control Schedule | Monitoring and Controlling | Work Performance measurements,
Change Requests |
The Define Activities process has the following Inputs, Tools and Techniques and Outputs -
Define Activities Process
| Inputs | Tools and Techniques | Outputs |
| Scope baseline | Decomposition | Activity list |
| Enterprise environmental factors | Rolling wave planning | Activity attributes |
| Organizational process assets | Templates | Milestone list |
| | Expert judgment | |
The Sequence Activities process has the following Inputs, Tools and Techniques and Outputs -
Sequence Activities Process
| Inputs | Tools and Techniques | Outputs |
| Project scope statement | Precedence diagram method (PDM) or AON | Project schedule network diagrams |
| Activity List | Applying leads and lags | Project document updates |
| Activity attributes | Schedule Network Templates | |
| Milestone list | Dependency determination | |
| Organizational process assets | | |
The Estimate Activity Resources process has the following Inputs, Tools and Techniques and Outputs -
Estimate Activity Resources Process
| Inputs | Tools and Techniques | Outputs |
| Activity List | Expert judgment | Activity resource requirements |
| Activity attributes | Alternative analysis | Resource breakdown structure |
| Resource calendars | Published estimating data | Project document updates |
| Enterprise environmental factors | Bottom-up estimating | |
| Organizational process assets | Project Management software | |
The Estimate Activity Durations process has the following Inputs, Tools and Techniques and Outputs -
Estimate Activity Durations Process
| Inputs | Tools and Techniques | Outputs |
| Activity list | Expert judgment | Activity duration estimates |
| Activity attributes | Analogous estimating | Project document updates |
| Activity resource requirements | Parametric estimating | |
| Resource calendars | Three-point estimates | |
| Project scope statement | Reserve analysis | |
| Enterprise environmental factors | | |
| Organizational process assets | | |
The Develop Schedule process has the following Inputs, Tools and Techniques, and Outputs-
Develop Schedule Process
| Inputs | Tools and Techniques | Outputs |
| Organizational process assets | Schedule network analysis | Project Schedule |
| Project scope statement | Critical path method | Schedule baseline |
| Activity List | Schedule Compression | Schedule data |
| Activity attributes | What-if scenario analysis | Project document updates |
| Project Schedule Network diagram | Resource levelling | |
| Activity Resource requirements | Critical chain method | |
| Resource Calendars | Scheduling tool | |
| Activity duration estimates | Applying calendars | |
Project Management Plan -
Risk Register | Adjusting Leads and Lags | |
| Enterprise environmental factors | | |
The Control Schedule process has the following Inputs, Tools and Techniques and Outputs -
Control Schedule Process
| Inputs | Tools and Techniques | Outputs |
| Project management plan | Performance reviews | Work performance measurements |
| Project schedule | Variance analysis | Organizational process assets updates |
| Work performance information | Project management software | Change requests |
| Organizational process assets | Resource leveling | Project management plan updates |
| | What-if scenario analysis | Project document updates |
| | Adjusting leads and lags | |
| | Schedule compression | |
| | Scheduling tool | |
Bar charts (or Gantt charts) are used to display tasks and their dates in a graphical fashion. They are used
to display information of the type task 1 is scheduled from date A to date B. Typically the
date range is displayed in the X-axis and the tasks on the Y-axis.
Bar charts do not show task dependencies. They are generally used to track progress and show to the team.
Milestone charts are similar to bar charts but display only major events. They display major
milestones (for example bridge design completed). They are used to report status to Management.
Network diagrams are used to display activities and their dependencies.
Network diagrams can be used to perform critical path analysis. Network diagrams can also be used
to perform crashing and fast tracking of the project.
There are two type of network diagrams -
- Activities on Node (or Precedence)
- Activities on Arrow (or AOA)
Precedence is most commonly used. AON and AOA cannot have loops or conditional relationships.
An activity in a network diagram is displayed as shown below.
| Activity name |
| Activity Number | Estimate |
As an example -
In the above example Documentation is activity number 2 and is estimated to last 5 days.
Precedence (or Activity on Node) diagrams can be used to display four type of relationship between
activities. These are
- Finish-To-Start
- Start-To-Start
- Start-To-Finish
- Finish-To-Finish
Finish-to-start relationship means the dependent activity cannot start until the first activity
is finished. This is the most common way to represent relationships between activities.
Activity on Array (AOA) network diagrams have the following characteristics.
- AOA only uses Finish-To-Start relationship between tasks.
- PERT and CPM can only be used with AOA.
- Dummy events are shown with dotted lines. They do not take any time. They show
dependencies between tasks.
Longest path through the network diagram is called the critical path. The activities on the critical
paths are called critical activities.
Lags are inserted waiting times in between tasks. For example Task B cannot start until three
days after task A completes.
Slack or Float is the amount of time a task can be delayed without delaying the project. Tasks on
the critical path have zero float.
Critical Path Method (CPM) has the following characteristics.
- It uses one time estimate per activity
- It can be drawn only using AOA diagrams
- It can have dummy events
Program Evaluation and Review Technique (PERT) has the following characteristics.
- It uses three estimates per activity - optimistic, pessimistic and most likely
- It can be drawn only using AOA diagrams
- It can have dummy events
PERT utilizes more information than CPM as it considers the
"Pessimistic" and "Optimistic" values in addition to the "Most Likely"
value in its calculations. The following are formulae used
by PERT -
Mean = (P + 4M + O)/6
Standard Deviation = (P-O)/6
Variance = ((P-O)/6)2
Here P is the pessimistic estimate, O is the optimistic estimate and M is the most likely estimate.
GERT is another type of network diagram. It can support looping.
If a project has more than one critical paths then the risk to the project increases.
Resource levelling refers to keeping the resources same across the duration of the project.
Questions on Project Schedule Management are available in
Schedule Questions.
UP NEXT: Cost Management