The Importance of Project Schedules
In project time management, the main output of defining activities are an activity list, activity attributes, a milestone list, and project management plan updates.
Estimating activity resources involves estimating how many resources— people, equipment, and materials—a project team should use to perform project activities. In project time management, this process follows after sequencing activities.
Plan schedule management
Project schedules grow out of the basic documents that initiate a project. The project charter often mentions planned project start and end dates, which serve as the starting points for a more detailed schedule.
A schedule management plan includes information on reporting formats. This information describes the format and frequency of schedule reports required for the project. In addition, it also includes information on process descriptions and describes how all of the schedule management processes will be performed.
Define activities
The goal of defining activities is to ensure that the project team completely understands all the work it must do as part of the project scope so the team can start scheduling the work. Activity information is a required input to the other time management processes.
Defining activities involves identifying the specific actions that will produce the project deliverables in enough detail to determine resource and schedule estimates. The project team reviews the schedule management plan, scope baseline, enterprise environmental factors, and organizational process assets to begin defining activities.
The activity list is a tabulation of activities to be included on a project schedule. The list should include the activity name, an activity identifier or number, and a brief description of the activity. The activity attributes provide more schedule-related information about each activity, such as predecessors, successors, logical relationships, leads and lags, and so forth.
Milestones
- A milestone is a significant event that normally has no duration.
- It often takes several activities and a lot of work to complete a milestone.
Milestones should be
- Specific
- Measurable
- Assignable
- Realistic
- Time-framed
Sequence activities
After defining project activities, the next step in project time management is sequencing them or determining their dependencies. The sequencing process involves evaluating the reasons for dependencies and the different types of dependencies.
In project time management, the main outputs of the sequencing activities process are an activity list, activity attributes, a milestone list, and project management plan updates.
The precedence diagramming method offers a number of advantages over the AOA technique. One advantage is that using this method avoids the need to use dummy activities.
Dependencies
- Mandatory dependencies
- Discretionary dependencies
- External dependencies
Mandatory dependencies are inherent in the nature of work being performed on a project. They are sometimes referred to as hard logic.
Discretionary dependencies are defined by the project team. They are sometimes referred to as soft logic and should be used with care because they may limit later scheduling options.
Network Diagrams
Arrow Diagramming Method
can only show finish-to-start dependencies
Precedence Diagramming Method
Task Dependency Types
When creating an AOA network diagram, bursts occur when two or more activities follow a single node.
Estimate activity resources
In project time management, before one can estimate the duration for each activity, one must have a good idea of the quantity and type of resources (people, equipment, and materials) that will be assigned to each activity.
Estimate activity durations
Duration includes the actual amount of time worked on an activity plus elapsed time.
Effort is the number of workdays or work hours required to complete a task
Duration 和 Effort 的区别？
不要把工期人工量混淆，后者是完成任务所需要的工作天数或者工作小时数
Duration estimates can be provided as a discrete number, a range, or as a three-point estimate.
Develop schedule
- 甘特图
- 关键路径分析
- 关键链进度法
- PERT分析
Critical Path Method(CPM)
Slack or float is the amount of time an activity may be delayed without delaying a succeeding activity or the project finish date
浮动时间的计算
活动最迟开始时间 - 活动最早开始时间（LS-ES)
活动最迟结束时间 - 活动最早结束时间 （LF-EF）
A backward pass through the network diagram determines the late start and late finish dates for each activity. In contrast, a forward pass determines the early start and early finish dates for each activity.
Knowing the amount of float allows project managers to know whether a project schedule is flexible.
Crashing is a technique for making cost and schedule trade-offs to obtain the greatest amount of schedule compression for the least incremental cost. The main advantage of crashing is shortening the time needed to finish a project.
The main advantage of crashing is that it shortens the time needed to finish a project. The main disadvantage is that it often increases total project costs.
Fast tracking involves doing activities in parallel that one would normally do in sequence. The main advantage of fast tracking is that it can shorten the time needed to finish a project.
The main disadvantage of fast tracking is that it can lengthen the project schedule because starting some tasks too soon often increases project risk and results in rework.
A tracking Cantt chart compares planned and actual projecy schedule information.
A white diamond on a Tracking Gantt chart represents a slipped milestone
The Theory of Constraints(TOC) is based on the fact that any complex system at any point in time often has only one aspect or constraint that limits its ability to achieve more of its goal.
Mulititasking occurs when a resource works on more than one task at a time.
Control schedule
The final process in project time management is controlling the schedule Like scope control, schedule control is a portion of the integrated change control process under project integration management.
The main outputs of schedule control include work performance measurements, organizational process assets updates such as lessons-learned reports related to schedule control, change requests, project management plan updates, and project documents updates.
One of the first reality checks on scheduling that a project manager should make is to review the draft schedule
Using the Critical Path to Shorten a Project Schedule
- Shortening durations of critical activities/tasks by adding more resources or changing their scope
- Crashing activities by obtaining the greatest amount of schedule compression for the least incremental cost
- Fast tracking activities by doing them in parallel or overlapping them
Critical Chain Scheduling
关键链调度
PERT
probabilistic time estimates
PERT weighted average = (optimistic time + 4 * most likely time + pessimistic time) / 6
杂项
A drawback of using templates or sample files is that managers and their teams might rely heavily on them and ignore unique concerns for their particular projects.
Q&A
1.There are three basic reasons () for creating dependencies among project activities.
参考上面的摘抄
2.Techniques for shortening a Project Schedule include ()
A. Shortening durations of critical tasks for adding more resources or changing their scope
B. Add project taks
C. Fast tracking task by doing them in parallel or overlapping them
D. Crashing tasks by obtaining the greatest amount of schedule compression for the least incremental cost
ABC
3.一道计算PERT weighted average 的题目
4.简要描述一下时间管理的过程
5.什么是里程碑
6.什么是网络图？描述两种网络图
7.描述关键路径分析. 关键路径如何计算
8.什么是TOC. 描述关键路径调度与TOC的应用