2. Project Time Management
Involves the processes required to ensure timely completion of
a project.
Seven main processes:
1. Planning schedule management
2. Defining activities
3. Sequencing activities
4. Estimating activity resources
5. Estimating activity durations
6. Developing the schedule
7. Controlling the schedule
3.
4. 1. PLANNING SCHEDULE MANAGEMENT
Includes the following information:
o Project schedule model development
o The scheduling methodology and the scheduling tool to
use when developing the project schedule model
o Level of accuracy and units of measure
o Control thresholds
o Rules of performance measurement
o Reporting formats
o Process descriptions
Output: schedule management plan
5. 2. DEFINING ACTIVITIES
Goal: 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.
Involves identifying the specific actions that will
produce the project deliverables in enough detail
to determine resource and schedule estimates.
Output: activity list, activity attributes, milestone list,
and project management plan updates
6. Activity list - 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.
Activity attribute - provide more schedule-related
information about each activity, such as
predecessors, successors, logical relationships, leads
and lags, resource requirements, constraints,
imposed dates, and assumptions related to the
activity.
Milestone - a significant event that normally has no
duration.
7. Activity information - required input to the other
time management processes.
You cannot determine activity sequencing,
resources, or durations, develop the schedule, or
control the schedule until you have a good
understanding of project activities.
8. 3. SEQUENCING ACTIVITIES
Done after defining project activities
Involves evaluating the reasons for dependencies
and the different types of dependencies.
Input: schedule management plan, activity list and
attributes, project scope statement, milestone list,
and organizational process assets.
Output: project schedule network diagrams and
project documents updates.
9. Dependency or relationship - pertains to the
sequencing of project activities or tasks.
Determining relationships or dependencies among
activities has a significant impact on developing
and managing a project schedule.
Three reasons for dependencies in project activities:
1. Mandatory dependencies
2. Discretionary dependencies
3. External dependencies
10. Network Diagram - preferred technique for showing
activity sequencing.
A schematic display of the logical relationships among project
activities and their sequencing
11.
12. Four types of dependencies or relationships:
1. Finish-to-start dependency: A relationship in which the
“from” activity or predecessor must finish before the “to”
activity or successor can start.
2. Start-to-start dependency: A relationship in which the
“from” activity cannot start until the “to” activity or
successor is started.
3. Finish-to-finish dependency: A relationship in which the
“from” activity must be finished before the “to” activity
can be finished. One task cannot finish before another
finishes.
4. Start-to-finish dependency: A relationship in which the
“from” activity must start before the “to” activity can be
finished. This type of relationship is rarely used, but it is
appropriate in some cases.
13.
14. Precedence diagramming method - used more often than
AOA network diagrams and offers a number of advantages
over the AOA technique.
Most project management software uses the precedence
diagramming method.
Using this method avoids the need to use dummy activities.
This shows different dependencies among tasks, whereas AOA
network diagrams use only finish- to-start dependencies.
15. 4. ESTIMATING ACTIVITY RESOURCES
Having a good idea of the quantity and type of
resources (people, equipment, and materials) that will
be assigned to each activity.
Nature of the project and the organization will affect
resource estimates.
The people who help determine what resources are
necessary must have experience and expertise in similar
projects and with the organization performing the
project.
Output: activity resource requirements, a resource
breakdown structure, and project documents updates.
16. Important questions to answer when estimating activity
resources:
o How difficult will specific activities be on this project?
o Is anything unique in the project’s scope statement that will
affect resources?
o What is the organization’s history in doing similar activities? Has
the organization done similar tasks before? What level of
personnel did the work?
o Does the organization have people, equipment, and
materials that are capable and available for performing the
work? Could any organizational policies affect the availability
of resources?
o Does the organization need to acquire more resources to
accomplish the work? Would it make sense to outsource some
of the work? Will outsourcing increase or decrease the
amount of resources needed and when they will be
available?
17. Resource breakdown structure - a hierarchical
structure that identifies the project’s resources by
category and type.
Resource categories might include analysts,
programmers, and testers. Types of programmers
might include Java programmers or COBOL
programmers.
18. 5. ESTIMATING ACTIVITY DURATIONS
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.
Three-point estimate includes:
o Optimistic estimate
o most likely estimate
o pessimistic estimate
19. 6. DEVELOPING THE SCHEDULE
Schedule development uses the results of all the
preceding project time management processes to
determine the start and end dates of the project and its
activities.
Project time management processes often go through
several iterations before a project schedule is finalized.
Goal: to provide a basis for monitoring project progress
for the time dimension of the project.
Output: project schedule, a schedule baseline, schedule
data, project calendars, project management plan
updates, and project documents updates.
20. Several tools and techniques for schedule
development:
o Gantt chart
o Critical path analysis
o Critical chain scheduling
o PERT analysis
21. Gantt charts - provide a standard format for displaying project
schedule information by listing project activities and their
corresponding start and finish dates in calendar form.
22. Different symbols on the Gantt chart :
o black diamond represents a milestone.
o thick black bars with arrows at the beginning and end
represent summary tasks.
o light gray horizontal bars represent the duration of each
individual task.
o Arrows connecting these symbols show relationships or
dependencies between tasks.
*Gantt charts often do not show dependencies, which is their
major disadvantage.
23.
24. Best Practice
(Luc Richard founder of www.projectmangler.com)
The five key points of using project milestones include the following:
1. Define milestones early in the project and include them in the Gantt chart to
provide a visual guide.
2. Keep milestones small and frequent.
3. The set of milestones must be all-encompassing.
4. Each milestone must be binary, meaning it is either complete or incomplete.
5. Carefully monitor the critical path.
Additional best practices for software development projects include the
following:
Monitor the project’s progress and revise the plan.
Build on a solid base.
Assign the right people to the right tasks.
Start with high-risk tasks.
“ Don’t boil the ocean.” - if the entire project consists of high-risk tasks, then
the project itself is a high risk and bound for failure.
Integrate early and often, and follow practices like the daily build process
25.
26. Critical path method (CPM) - a network
diagramming technique used to predict total
project duration. This helps you combat project
schedule overruns.
Critical path - series of activities that determine the
earliest time by which the project can be
completed.
Slack or float - is the amount of time an activity may
be delayed without delaying a succeeding activity
or the project finish date.
27. Calculating the Critical Path:
Add the durations for all activities on each path through the network
diagram. The longest path is the critical path.
28. A technique that can help project managers make
schedule trade-offs is determining the free slack and
total slack for each project activity.
Free slack or free float - the time an activity can be
delayed without delaying the early start date of any
immediately following activities.
Total slack or total float – the time an activity can be
delayed from its early start without delaying the planned
project finish date.
Project managers calculate free slack and total slack by
doing a forward and backward pass through a network
diagram.
29.
30. Two Techniques to Use Critical Path to Shorten a
Project Schedule:
1. Crashing- is a technique for making cost and
schedule trade-offs to obtain the greatest
amount of schedule compression for the least
incremental cost
2. Fast tracking - involves doing activities in parallel
that you would normally do in sequence.
Note: It is important to update the schedule with
actual data. These revisions often cause a project’s
critical path to change, resulting in a new
estimated completion date for the project.
31. Critical Chain Scheduling
Another technique that is the application of TOC that
addresses the challenge of meeting or beating project finish
dates
A method that considers limited resources when creating a
project schedule and includes buffers to protect the project
completion date.
The availability of scarce resources. Some projects cannot be
done unless a particular resource is available to work on one
or several tasks.
Assumes that resources do not multitask or at least minimize
multitasking.
32.
33. Critical chain scheduling removes buffers from
individual tasks and instead creates a project
buffer, which is time added before the project’s
due date.
Critical chain scheduling protects tasks on the
critical chain from being delayed by using feeding
buffers.
The task estimates in critical chain scheduling
should be shorter than traditional estimates
because they do not include their own buffers.
34.
35. Program Evaluation and Review Technique (PERT) –
a network analysis technique used to estimate
project duration when there is a high degree of
uncertainty about the individual activity duration
estimates.
Applies the critical path method (CPM) to a
weighted average duration estimate.
uses probabilistic time estimates based on using
optimistic, most likely, and pessimistic estimates of
activity durations:
36. By using the PERT weighted average for each
activity duration estimate, the total project duration
estimate takes into account the risk or uncertainty
in the individual activity estimates.
Advantage: Attempts to address the risk associated
with duration estimates and may help in developing
schedules that are more realistic
Disadvantage: More work than CPM because it
requires several duration estimates, and there are
better probabilistic methods for assessing schedule
risk.
37. 7. CONTROLLING THE SCHEDULE
A portion of the integrated change control process
under project integration management.
Goal to know the status of the schedule, influence the
factors that cause schedule changes, determine that
the schedule has changed, and manage changes
when they occur.
Input: project management plan, project schedule,
work performance data, project calendars, schedule
data, and organizational process assets.
Output: 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.
38. Some of the tools and techniques include:
o Performance reviews
o A schedule change control system
o A scheduling tool and/or project management software,
such as Project 2010 or similar software
o Variance analysis,
o What-if scenario analysis
o Adjusting leads and lags
o Schedule compression
o Resource optimization techniques
39. Reality Checks and Needed Discipline
Review the draft schedule that is usually included in the project
charter.
Prepare a more detailed schedule and get stakeholders’
approval.
Progress meetings with stakeholders.
Use discipline to control project schedules.
Do not rely too much on project management software.
Understand the concepts behind creating a network diagram,
determining the critical path, or setting a schedule
Understand the underlying concepts to successful use of project
management software, as is understanding the specific needs of
your project.
Notes de l'éditeur
Project Schedules are important because:
Managers often cite the need to deliver projects on time as one of their biggest challenges and the main cause of conflict because it is easily mmeasured and remembered.
Time is the variable that has the least amount of flexibility. Time passes no matter what happens on a project.
Seven main processes are involved in project time management:
Planning schedule management involves determining the policies, procedures, and documentation that will be used for planning, executing, and controlling the project schedule.
2. Defining activities involves identifying the specific activities that the project team members and stakeholders must perform to produce the project deliverables. An activity or task is an element of work normally found on the work breakdown structure (WBS) that has expected duration, cost, and resource requirements.
3. Sequencing activities involves identifying and documenting the relationships between project activities.
4. Estimating activity resources involves estimating how many resources— people, equipment, and materials—a project team should use to perform project activities.
5. Estimating activity durations involves estimating the number of work periods that are needed to complete individual activities. Outputs include activity duration estimates and project documents updates.
6. Developing the schedule involves analyzing activity sequences, activity resource estimates, and activity duration estimates to create the project schedule. Outputs include a schedule baseline, project schedule, schedule data, project calendars, project management plan updates, and project documents updates.
7. Controlling the schedule involves controlling and managing changes to the project schedule. Outputs include work performance information, schedule forecasts, change requests, project management plan updates, project documents updates, and organizational process assets updates.
The first step in project time management is planning how the schedule will be managed throughout the life of the project. Project schedules grow out of the basic documents that initiate a project.
Includes the following information:
Project schedule model development: Many projects include a schedule model, which contains project activities with estimated durations, dependencies, and other planning information that can be used to produce a project schedule.
The scheduling methodology and the scheduling tool to use when developing the project schedule model: Some projects will use critical path or critical chain methodologies, for example, while simpler projects might focus only on milestones.
Level of accuracy and units of measure: This section discusses how accurate schedule estimates should be and determines whether time is measured in hours, days, or another unit.
Control thresholds: Variance thresholds, such as ±10%, are established for monitoring schedule performance.
Rules of performance measurement: For example, if earned value management (EVM) will be used, this section specifies how.
Reporting formats: This section describes the format and frequency of schedule reports required for the project.
Process descriptions: The schedule management plan also describes how all of the schedule management processes will be performed.
The activity list and activity attributes should be in agreement with the WBS and WBS dictionary.
Information is added to the activity attributes as it becomes available; this information includes logical relationships and resource requirements that are determined in later processes.
Milestone - a significant event that normally has no duration. It often takes several activities and a lot of work to complete a milestone, but the milestone itself is like a marker to help in identifying necessary activities. Milestones are also useful tools for setting schedule goals and monitoring progress.
Activity information - required input to the other time management processes. You cannot determine activity sequencing, resources, or durations, develop the schedule, or control the schedule until you have a good understanding of project activities. Recall the triple constraint of project management—balancing scope, time, and cost goals—and note the order of these items. Ideally, the project team and key stakeholders first define the project scope, then the time or schedule for the project, and then the project’s cost. The order of these three items reflects the basic order of the processes in project time management: defining activities (further defining the scope), sequencing activities (further defining the time), and estimating activity resources and activity durations (further defining the time and cost). These four project time management processes are the basis for creating a project schedule.
For example, does a certain activity have to be finished before another can start? Can the project team do several activities in parallel? Can some overlap?
There are three basic reasons for creating dependencies among project activities:
• Mandatory dependencies are inherent in the nature of the work being per- formed on a project. They are sometimes referred to as hard logic. For exam- ple, you cannot test code until after the code is written.
• Discretionary dependencies are defined by the project team. For example, a project team might follow good practice and not start the detailed design of a new information system until the users sign off on all of the analysis work. Discretionary dependencies are sometimes referred to as soft logic and should be used with care because they may limit later scheduling options.
• External dependencies involve relationships between project and non-project activities. For example, the installation of a new operating system and other software may depend on delivery of new hardware from an external supplier. Even though delivery of the hardware may not be included in the scope of the project, you should add an external dependency to it because late delivery will affect the project schedule.
Some people refer to network diagrams as project schedule network dia- grams or PERT charts. PERT is described later in this chapter. Figure 6-2 shows a sample network diagram for Project X.
Note the main elements on this network diagram. The letters A through J represent activities with dependencies that are required to complete the project. These activities come from the WBS and activity definition process described earlier. The arrows represent the activity sequencing or relationships between tasks.
For example, Activity A must be done before Activity D, and Activity D must be done before Activity H. The format of this network diagram uses the activity-on-arrow (AOA) approach or the arrow diagramming method (ADM)—a network diagramming technique in which activities are represented by arrows and connected at points called nodes to illustrate the sequence of activities.
Node - the starting and ending point of an activity.
The first node signifies the start of a project, and the last node represents the end.
Keep in mind that the network diagram represents activities that must be done to complete the project. It is not a race to get from the first node to the last node. Every activity on the network diagram must be completed in order to finish the project. Note also that not every item on the WBS needs to be shown on the network diagram; only activities
the types of dependencies that can occur among project activities based on a Microsoft Project help screen. After you determine the reason for a dependency between activities (mandatory, discretionary, or external), you must determine the type of dependency. Note that the terms activity and task are used interchangeably, as are relationships and dependencies
Finish-to-start dependency: A relationship in which the “from” activity or predecessor must finish before the “to” activity or successor can start. For example, you cannot provide user training until after software or a new system has been installed. Finish-to-start is the most common type of relationship or dependency, and AOA network diagrams use only finish-to-start dependencies.
Start-to-start dependency: A relationship in which the “from” activity cannot start until the “to” activity or successor is started. For example, on IT projects, a group of activities might start simultaneously, such as the many tasks that occur when a new system goes live.
Finish-to-finish dependency: A relationship in which the “from” activity must be finished before the “to” activity can be finished. One task cannot finish before another finishes. For example, quality control efforts cannot finish before production finishes, although the two activities can be performed at the same time.
Start-to-finish dependency: A relationship in which the “from” activity must start before the “to” activity can be finished. This type of relationship is rarely used, but it is appropriate in some cases. For example, an organization might strive to stock raw materials just in time for the manufacturing process to begin. A delay in starting the manufacturing process should delay completion of stocking the raw materials. Another example would be a babysitter who wants to finish watching a young child but is dependent on the parent’s arrival. The parent must show up or “start” before the babysitter can finish the task
Precedence diagramming method. Notice that the activities are placed inside boxes, which represent the nodes on this diagram. Arrows show the relationships between activities. This figure was created using Microsoft Project, which automatically places additional information inside each node. Each task box includes the start and finish dates, which are labeled Start and Finish; the task ID number, labeled ID; the task’s duration, labeled Dur; and the names of resources, if any, that are assigned to the task. These resources are labeled Res. The border of boxes for tasks on the critical path appears automatically in red in the Microsoft Project netw ork diagram view. In Figure 6-4, the boxes for critical tasks have a thicker border.
Dummy activities have no duration and no resources, but are occasionally needed on AOA network diagrams to show logical relationships between activities. These activities are represented with dashed arrow lines, and have zeros for their duration estimates.
Answering these questions requires important inputs such as a project’s schedule management plan, activity list, activity attributes, resource calendars, risk register, activity cost estimates, enterprise environmental factors, and organizational process assets such as policies regarding staffing and outsourcing.
During the early phases of a project, the project team may not know which specific people, equipment, and materials will be available. For example, the team might know from past projects that a mix of experienced and inexperienced programmers will work on a project.
The team might also be able to approximate the number of people or hours needed to perform specific activities. It is important to thoroughly brainstorm and evaluate alternatives related to resources, especially on projects that involve people from multiple disciplines and companies. Because most projects involve many human resources and the majority of costs are for salaries and benefits, it is often effective to solicit ideas from different people to help develop alternatives and address resource-related issues early in a project. The resource estimates should also be updated as more detailed information becomes available.
This information would be helpful in determining resource costs, acquiring resources, and so on.
After working with key stakeholders to define activities, determine their dependencies, and estimate their resources, the next process in project time management is to estimate the duration of activities.
Duration: For example, even though it might take one workweek or five workdays to do the actual work, the duration estimate might be two weeks to allow extra time needed to obtain outside information.
Three-point estimate: example: three weeks for the optimistic scenario, four weeks for the most likely scenario, and five weeks for the pessimistic estimate. The optimistic estimate is based on a best-case scenario, while the pessimistic estimate is based on a worst-case scenario. The most likely estimate, as you might expect, is based on a most likely or expected scenario. A three- point estimate is required for performing PERT estimates
A Gantt chart - is a common tool for displaying project schedule information.
Critical path analysis - is a very important tool for developing and controlling project schedules.
Critical chain scheduling - is a technique that focuses on limited resources when creating a project schedule.
PERT analysis - is a means for considering schedule risk on projects.
Gantt charts are sometimes referred to as bar charts because the activities’ start and end dates are shown as horizontal bars.
Advantage of using Gantt charts:
- it provides a standard format for displaying planned and actual project schedule information.
- easy to create and understand.
Disadvantage:
- do not usually show relationships or dependencies between tasks
Although, If dependencies have been established in Microsoft Project, they are automatically displayed on the Gantt chart.
Milestones can be a particularly important part of schedules, especially for large projects.
To make milestones meaningful, some people use the SMART criteria to help define them. The SMART criteria are guidelines suggesting that milestones should be:
• Specific
• Measurable
• Assignable
• Realistic
• Time-framed
Additional best practices for software development projects include the following:
Monitor the project’s progress and revise the plan.
Build on a solid base; that means developing a system with less than a 0.1 percent defect rate.
Assign the right people to the right tasks. Put the best developers on the critical tasks.
Start with high-risk tasks.
“ Don’t boil the ocean.” - if the entire project consists of high-risk tasks, then the project itself is a high risk and bound for failure.
Integrate early and often, and follow practices like the daily build process. (A daily build involves compiling the latest version of a software program each day to ensure that all required dependencies are present and that the program is tested to avoid introducing new bugs.
Using Tracking Gantt Charts to Compare Planned and Actual Dates You can use a special form of a Gantt chart to evaluate progress on a project by show- ing actual schedule information. A Tracking Gantt chart is based on the percentage of work completed for project tasks or the actual start and finish dates. It allows the project manager to monitor schedule progress on individual tasks and the whole project. For example, Figure 6-7 shows that the
project is completed. It started on time, but it finished a little late, on May 13 (5/13)
instead of May 8.
Critical path method (CPM) - also called critical path analysis—is a network diagramming technique used to predict total project duration. This helps you combat project schedule overruns. A critical path for a project is the series of activities that determine the earliest time by which the project can be completed. It is the longest path through the network diagram and has the least amount of slack or float.
A technique that can help project managers make schedule trade-offs is determining the free slack and total slack for each project activity.
Free slack or free float - the amount of time an activity can be delayed without delaying the early start date of any immediately following activities. The early start date is the earliest possible time an activity can start based on the project network logic.
Total slack or total float is the amount of time an activity can be delayed from its early start without delaying the planned project finish date.
Project managers calculate free slack and total slack by doing a forward and backward pass through a network diagram.
A forward pass determines the early start and early finish dates for each activity. The early finish date is the earliest possible time an activity can finish based on the project network logic.
A much faster and easier way to determine early and late start and finish dates and free
and total slack amounts for activities is by using project management software.
Two Techniques to Use Critical Path to Shorten a Project Schedule:
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 disadvantage of crashing is that it often increases total project costs.
Fast tracking - involves doing activities in parallel that you would normally do in sequence.
The main advantage of fast tracking, like crashing, is that it can shorten the time needed to finish a project. The main disadvantage is that it can lengthen the project schedule because starting some tasks too soon often increases project risk and results in rework.
Another technique that addresses the challenge of meeting or beating project finish dates is an application of the Theory of Constraints called critical chain scheduling. The Theory of Constraints (TOC) is a management philosophy developed by Eliyahu M. Goldratt and discussed in his books The Goal and Critical Chain.
The Theory of Constraints is based on the metaphor of a chain and its weakest link: Any complex system at any point in time often has only one aspect or constraint that limits the ability to achieve more of the system’s goal.
For the system to attain any significant improvements, that constraint must be identified, and the whole system must be managed with it in mind. Critical chain scheduling is a method that considers limited resources when creating a project schedule and includes buffers to protect the project completion date.
An important concept in critical chain scheduling is the availability of scarce resources. Some projects cannot be done unless a particular resource is available to work on one or several tasks.
Multitasking occurs when a resource works on more than one task at a time. This situation occurs frequently on projects. People are assigned to multiple tasks within the same project or different tasks on multiple projects.
Sometimes, Multitasking also often involves wasted setup time, which increases total duration.
Someone should not be assigned to two tasks simultaneously on the same project when critical chain scheduling is in effect. Likewise, critical chain theory suggests that projects be prioritized so that people who are working on more than one project at a time know which tasks take priority. Preventing multitasking avoids resource conflicts and wasted setup time caused by shifting between multiple tasks over time.
Murphy’s Law states that if something can go wrong, it will. Critical chain scheduling removes buffers from individual tasks and instead creates a project buffer, which is time added before the project’s due date. Critical chain scheduling also protects tasks on the critical chain from being delayed by using feeding buffers, which consist of time added before tasks on the critical chain if they are preceded by other tasks that are not on the critical path.
The task estimates in critical chain scheduling should be shorter than traditional estimates because they do not include their own buffers.
Not having task buffers should mean fewer occurrences of Parkinson’s Law, which states that work expands to fill the time allowed. The feeding and project buffers protect the date that really needs to be met—the project completion date.
Some of the tools and techniques include:
• Performance reviews, where progress reports are often provided
• A schedule change control system, operated as part of the integrated change control system described in Chapter 4, Project Integration Management
• A scheduling tool and/or project management software, such as Project 2010 or similar software
• Variance analysis, such as analyzing float or slack and using earned value, as described in Chapter 7, Project Cost Management
• What-if scenario analysis, which can be done manually or with the aid of software
• Adjusting leads and lags
• Schedule compression, such as crashing and fast tracking, as described earlier in this chapter
• Resource optimization techniques, such as resource leveling, as described in Chapter 9, Project Human Resource Management
Review the draft schedule that is usually included in the project charter. Although this draft schedule might include only a project start and end date, the project charter sets some initial schedule expectations for the project.
Prepare a more detailed schedule and get stakeholders’ approval. To establish the schedule, it is critical to get involvement and commitment from all project team members, top management, the customer, and other key stakeholders.
Progress meetings with stakeholders. The project manager is responsible for keeping the project on track, and key stakeholders like to stay informed, often through high-level periodic reviews.
Use discipline to control project schedules. Several IT project managers have discovered that setting firm dates for key project milestones helps minimize schedule changes.