Project Time Management: Notes for PMP Exam (based on PMBOK5)

Note:

These all  articles are dedicated to my teachers, my seniors, colleagues, internet bloggers, online technical material, reference books from where I learned all these. There are chances that the material presented here is duplicated somewhere on the web. If anything is replicated anywhere, I sincerely give proper credits to the contributor.

Project Time Management:

We are managing time here. That means we are managing schedule. Managing the schedule simply means controlling the schedule (Control Schedule). 

For controlling the schedule, we need to have a schedule. We have to develop a schedule for that (Develop Schedule).

How we will develop the schedule and what we need for that. It simple, we need activities (Define Activities) and we will sequence them i.e. we need to know when the execute them (Sequence Activities) and we will estimate the duration of these activities (Estimate Activity Durations). But activity durations depends on the type of resources i.e. more efficient resource will finish the activity earlier, so we need to estimate the activity resources (Estimate Activity Resources)

For all of the above we have to plan (Plan Schedule Management)

Did you notice how easily we have defined all the processes of Time Management. Here is the order:

• 1.  Plan Schedule Management
• 2. Define Activities
• 3. Sequence Activities
• 4. Estimate Activity Resources
• 5. Estimate Activity Durations
• 6. Develop Schedule
• 7. Control Schedule

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Plan Schedule Management

We define policies, procedures and documentation for managing and controlling project schedule which includes scheduling methodology, tools, level of accuracy, control thresholds (limit beyond which preventive/corrective actions needed, before threshold we don't take any actions e.g. we will not control the schedule for a delay of 6 hours ), rules of performance measurement (e.g. earned value etc. )

Inputs:
1 Project management plan
2 Project charter
3 Enterprise environmental factors
4 Organizational process assets

Tools & Techniques:
1 Expert judgment
2 Analytical techniques
3 Meetings

Output:
1 Schedule management plan

Point to remember: We use Analytical Techniques here.

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Define Activities

• We take WBS and further decompose Work Packages (last level of WBS) into activities. These activities are helpful for more detailed and accurate estimations.
• Activities are the work/process to produce the deliverables.
• There are different type of activities types: 

• Level of Efforts (support, measured in time period, it is measured by passage of time).
• Discrete efforts (Digital Efforts) 
• Apportioned Effort (in proportion to another discrete effort)

• Activities have durations while milestones do not have durations. They have ZERO Duration e.g. Painting complete (this has no duration, so it is a milestone)

 

Inputs

1 Schedule management plan
2 Scope baseline
3 Enterprise environmental factors
4 Organizational process assets

Tools & Techniques

1 Decomposition : We are decomposing WBS into activities.
2 Rolling wave planning: We define the activities for near term. For the work to be done later, we define activities later when are approaching that work.
3 Expert judgment

Outputs

1 Activity list
2 Activity attributes: An understanding of Activities. When, who, where, predecessor, successor, activity identifier etc.
3 Milestone list

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Sequence Activities

• We use Precedence Diagramming Method (PDM) to draw the dependencies. Note that this diagram only shows dependencies. It is also called AON (Activity on Node) Diagram.
• It can also duration, workflow, helps identifying critical paths.
• Precedence relationships : finish-to-start (mostly used), start-to-start, finish-to-finish, start-to-finish (least)
• Activity on Arrow (AOA) or Arrow Diagramming Method (ADM) activities are represented as arrows, dashed arrows represent dummy activities (duration: 0) that shows dependencies
• Graphical Evaluation and Review Technique (GERT) allows for conditional branching and loops.
• Network Dependency Types (to be determined during Sequence Activities Process):
• Mandatory Dependency (hard logic): A must be completed before B begins/ technical dependencies may not be hard
• Discretionary Dependency (preferred, soft logic): sequence preferred by the organization, may be removed should fast-tracking is required
• External Dependency: dependency required by external organization
• Internal Dependency: precedence relationship usually within the project team’s control

Team decides Mandatory and Discretionary and Project Manager (or PM Team) decides External and Internal dependencies.

• Milestone list is part of i) Project Management Plan, ii) Project Scope Statement, iii) WBS Dictionary. Major Milestones can be defined in Project Charter also.
• Leads: Begin successor activity before end of predecessor activity. These are shown as negative numbers.
• Lags: Imposed delay to successor activity, e.g. wait 2 weeks for concrete to dry. So Lag is simply waiting time.
• if the Early Start and Late Start are identical, the activity is on the critical path. It means activity has a Zero float. You can also say activity doesn't have scheduling flexibility.

Inputs:
1 Schedule management plan
2 Activity list
3 Activity attributes
4 Milestone list
5 Project scope statement
6 Enterprise environmental factors
7 Organizational process assets

Tools & Techniques:
1 Precedence diagramming method (PDM): We use PDM.
2 Dependency determination: We determine dependencies. See above
3 Leads and lags: We need to know how much delay or lead time we should have between the activities.

Outputs:
1 Project schedule network diagrams
2 Project documents updates
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Estimate Activity Resources

Here we estimate the resources for the activities. Because project schedule depends a lot on what type of resources we are using. If there is a skilled resource he may finish the work earlier.

• This process is closely related to Estimate Cost Process (See Cost Management)

• We need resource calendar which tells us the availability of resources.

• We need to do the alternative analysis while estimating the resource because we may have different alternatives.

Inputs:
1 Schedule management plan
2 Activity list
3 Activity attributes
4 Resource calendars
5 Risk register
6 Activity cost estimates
7 Enterprise environmental factors
8 Organizational process assets

Tools & Techniques:
1 Expert judgment
2 Alternative analysis
3 Published estimating data: Many organizations and unions publish the data about the resources like their skills, their rates etc.
4 Bottom-up estimating: This is an important technique. It will also be used in Cost Estimation.
5 Project management software: PM Software can help us to estimate resources.

Outputs:
1 Activity resource requirements
2 Resource breakdown structure: Here we get the resources defined by categories.
3 Project documents updates

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Estimate Activity Durations

Here we estimate the durations of activities. You may get couple of questions in the exam on this process.

• Team should be involved in estimation. If PM is doing the estimation himself / herself, that is not going to help.
• Analogous Estimating: based on previous activity with exactly similar nature (a form of expert judgement), used when little is known or very similar scope, works well when project is small, NOT ACCURATE. This comes from historical information. It is a technique which is not time consuming. If management wants immediate estimation, you always provide Analogous estimate.
• Parametric Estimating: based on  parameters (per unit of something: say Flooring tiles are 250 INR per dozen.
• One-Point Estimating: based on expert judgement, but highly unreliable. It involves padding. mostly based on guess.
• Three-Point Estimating: best (optimistic-O), realistic (most likely-M), worst (pessimistic-P) cases, Triangular Distribution vs PERT (Project Evaluation and Review Techniques, Beta Distribution, weighted average using statistical methods [most likely * 4 – 95% confidence level with 2 sigma]), triangular distribution (non-weighted average of three data points), uncertainties are accounted for.
• In real world applications, the PERT estimate is processed using Monte Carlo analysis, tie specific confidence factors to the PERT estimate.
• PERT gives us Pert Distribution which is PERT = (P+4M+O)/6 and Variance = (P-O)/6
• When you are give couple of variances you have to find the total variance, then you need to find the Standard Deviation of each and then find the Variance. 

           Variance = SQRT (SD1+SD2+SD3....) where SD1 = (VAR1)²

• Bottom-Up Estimating: It is a detailed estimate by decomposing the tasks and derive the estimates based on reliable historical values, most accurate but time-consuming and expensive.
• Heuristics: use rule of thumb for estimating. Generally accepted rule.
• Standard Deviation (sigma value, deviation from mean (not from median), to specify the precision of measurement): 1 sigma: 68%, 2 sigma 95%, 3 sigma 99.7%, 6 sigma 99.99%. Remember these value. They many appear in exam.
• Contingency reserve: for known unknowns, owned by PM, may be updated, part of schedule baseline. Known unknowns are the risks which are identified in advance.
• management reserve: for unknown unknowns, owned by management, included in overall schedule requirements. This is not part of Schedule baseline. Unknown unknowns are the risks which cannot be identified in advance.
• Activity duration estimate should be in a range.
• PERT estimation gives us a reliable range.

Inputs:
1 Schedule management plan
2 Activity list
3 Activity attributes
4 Activity resource requirements
5 Resource calendars
6 Project scope statement
7 Risk register
8 Resource breakdown structure
9 Enterprise environmental factors
10 Organizational process assets

Tools & Techniques:
1 Expert judgment
2 Analogous estimating
3 Parametric estimating
4 Three-point estimating
5 Group decision-making techniques
6 Reserve analysis

Outputs:
1 Activity duration estimates
2 Project documents updates

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Develop Schedule

*The process of analyzing activity sequences, durations, resource requirements, and schedule constraints to create the project schedule model.*Schedule model is a representation of the plan for executing the project’s activities including durations, dependencies, and other planning information, used to produce a project schedule along with other scheduling artifacts.
*These definitions are taken from the Glossary of the Project Management Institute, A Guide to the Project Management Body of Knowledge, (PMBOK® Guide)–Fifth Edition, Project Management Institute, Inc., 2013.

• The Schedule Baseline is the approved and signed version of project schedule that is incorporated into the PM plan. It can be changed only by the formal change control process.
• The schedule is calendar-based taking into accounts holidays/resource availability/vacations.
• Slack/Float: Activities that can be delayed without impacting the schedule.
• Free slack/float: time an activity can be delayed without delaying the Early Start of the successor
• Total slack/float: time an activity can be delayed from early start without delaying the project end date (scheduling flexibility), can be negative, 0 (on the critical path) or positive
• Project Float: without delaying the project.
• Negative float: problem with schedule, Project is behind. Replan, Rework.
• Project slack/float: time the project can be delayed without delaying another project
• Early Start (ES) – earliest time to start the activity
• Late Start (LS) – latest time to start without impacting the late finish
• Early Finish (EF) – earliest time to end the activity
• Late Finish (LF) – latest time to finish without impacting successor activity
• Slack/Float = LS – ES or LF – EF
• Critical Path: the longest path that amount to shortest possible completion time (usually zero float, activities with mandatory dependency with finish-to-start relationship), can have more than 1 critical paths (more risks), critical paths may change (keep an eye on near-critical paths).
• Activities on the critical path are called critical activities
• Path with negative float = behind schedule, need compression to eliminate negative float.
• Fast Tracking : allow overlapping of activities or activities in parallel, included risks/resource overloading. Always increasing risk. Look at the questions in exam. It may ask one critical path and one non critical path activity. So there is no advantage of fast tracking. Activities only on critical path can be fast tracked to compress the schedule.
• Crashing : shorten the activities by adding resources, may result in team burnout. It may also need to approve overtime.
• Scheduling Techniques
• Critical Path Method (CPM) – compute the forward and backward pass to determine the critical path and float
• Critical Chain Method (CCM) – deal with scarce resources and uncertainties, keep the resources levelly loaded by chaining all activities and grouping the contingency and put at the end as project buffer, for activities running in parallel, the contingency is called feeding buffer (expect 50% of activities to overrun)
• Buffer is determined by assessing the amount of uncertainties, human factors, etc.
• Parkinson’s Law: Work expands so as to fill the time available for its completion.
• Resource Optimization Techniques
• Resource leveling is used to adjust the variation in resource loading to stabilize the number of resources working each time and to avoid burnout, may need to extend the schedule in CPM
• Resource smoothing is to adjust resource requirements so as not to exceed predetermined resource limits, but only optimized within the float boundaries
• Modeling Techniques
• What if analysis: to address feasibility/possibility of meeting project schedule, useful in creating contingency plan
• Monte Carlo: run thousand of times to obtain the distribution using a set of random variables (stochastic variables), use a combination of PERT estimate and triangular distributions as end point estimates to create the model to eliminate schedule risks, the graph is a ‘S’ curve. It can be done only by using a computer.
• Hammock activities: higher-level summary activities between milestones
• Milestone Charts: show only major deliverables/events on the timeline
• Data date (status date, as-of date): the date on which the data is recorded. Please note here Earned value (we will discuss later) can be calculated on data date only. If you see a curve where EV is beyond the data date, curve is wrong.
• Schedule Data includes schedule milestones, schedule activities, activities attributes, and documentation of all assumptions and constraints, alternative schedules and scheduling of contingency reserves

  Inputs:
1 Schedule management plan
2 Activity list
3 Activity attributes
4 Project schedule network diagrams
5 Activity resource requirements
6 Resource calendars
7 Activity duration estimates
8 Project scope statement
9 Risk register
10 Project staff assignments
11 Resource breakdown structure
12 Enterprise environmental factors
13 Organizational process assets

Tools & Techniques:
1 Schedule network analysis
2 Critical path method
3 Critical chain method
4 Resource optimization techniques
5 Modeling techniques
6 Leads and lags
7 Schedule compression
8 Scheduling tool

Outputs:
1 Schedule baseline
2 Project schedule
3 Schedule data
4 Project calendars
5 Project management plan updates
6 Project documents updates


Question: What is the main benefit of this process? Answer: When you enter scheduling information in the scheduling tool, it generates schedule model with planned dates for completing project’s activities. 

Question: What information do you enter in the scheduling tool to generate schedule model? 
Answer: Activity list, logical relationships, resources, and resource availability! 

Question: For what purpose do we use schedule model? 
Answer: We use schedule model to determine the planned start and finish dates for project’s activities and milestones. But is it is based on accuracy of inputs! 

Question: What review and revision is required for schedule development in order to establish an approved schedule that can serve as a baseline to track progress? 
Answer: Review and revision of duration estimates and resource estimates. 

Question: What does this review mean? 
Answer: After activity start and finish dates are determined, project team assigned to these activities review to check whether these dates are still valid and do not conflict with resource calendars and assigned activities in other projects or tasks. 

Question: How do you sustain a realistic schedule throughout the project? 
Answer: As the work is performed and moves on, we revise and maintain schedule model to ensure we are able to sustain a Realistic Schedule.
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Control Schedule

The process of monitoring the status of the project activities to update project progress and manage changes to schedule baseline to achieve the plan. 
It gives us means to identify deviation from the plan and recommend corrective and preventive actions for mitigating risk.


For traditional projects 

• Find current status of project schedule-variance from the plan
• Manage factors that create schedule changes;
• Control impact of changes;
• Ensure that only approved changes are implemented; and
• Integrate approved schedule changes with other controlling processes.

Inputs:
1 Project management plan
2 Project schedule
3 Work performance data
4 Project calendars
5 Schedule data
6 Organizational process assets

Tools & Techniques:
1 Performance reviews
2 Project management software
3 Resource optimization techniques
4 Modeling techniques
5 Leads and lags
6 Schedule compression
7 Scheduling tool

Outputs:
1 Work performance information
2 Schedule forecasts
3 Change requests
4 Project management plan updates
5 Project documents updates
6 Organizational process assets updates