PMP Certification Study Notes 6 – Project Time Management


PMP Time Management

Introduction: This part of the PMP® exam study notes is based on chapter 6 of PMBOK® Guide 5th Edition. More information on my PMP® certification exam preparation can be found at my PMP® exam and certification journey here.

Plan Schedule Management

  • define policies, procedures and documentation for managing and controlling project schedule
  • including scheduling methodology, tools, level of accuracy, control thresholds (limit beyond which preventive/corrective actions needed), rules of performance measurement (e.g. earned value)
  • lead and lags are NOT schedule constraints

Define Activities

  • the scope baseline is used here as it represents the approved (stable) scope
  • further decompose work packages into activities for more detailed and accurate estimations
  • ‘activities’ is the PMI terminology for ‘tasks’ and ‘work efforts’
  • activity is more related to the actual work/process to produce the deliverables
  • activity types: level of efforts (support, measured in time period), discrete efforts or apportioned effort (in direct proportion to another discrete effort)
  • activities have durations while milestones do not (zero duration)

Sequence Activities

  • WBS is no longer needed, so the Project Scope Statement is the input rather than scope baseline
  • Precedence Diagramming Method (PDM) to diagram dependencies
  • Network Diagramming Tools are software tools that graphically represent activity sequences
  • network diagrams: shows dependencies, duration, workflow, helps identifying critical paths
  • precedence relationships (also known as ‘activity on node (AON)‘ approach): finish-to-start (~95%), 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
  • Milestones: the completion of a key deliverable/a phase in the project, as checkpoints/summary for progress, often used in funding vendor activities
  • Milestone list is part of i) project plan, ii) project scope statement, iii) WBS dictionary
  • Leads: begin successor activity before end of predecessor, for schedule compression (fast tracking) (negative lags)
  • Lags: imposed delay to successor activity, e.g. wait 2 weeks for concrete to cure (FS +14 days)
  • Network Diagram Setup : 7-box method, usually using software tools or 5-box method
  • if the ES and LS are identical, the activity is on the critical path

Estimate Activity Resources

  • closely related to Estimate Cost Process (in Cost Management)
  • resource calendar spells out the availability of resources (internal/external) during the project period
  • matches human resources to activities (as human resources will affect duration)
  • effort (man day, work week, etc.) vs duration vs time lapsed (total time needed, including holidays, time off)
  • alternative analysis includes make-or-buy decisions, different tools, different skills, etc.
  • Activity Resource Requirements may include the basis of estimation

Estimate Activity Durations

  • consults SME (subject matter experts, i.e. the one carrying out the actual work) to come with with the estimation, not on the PM’s own
  • Analogous Estimating: based on previous activity with similar nature (a form of expert judgement), used when little is known or very similar scope, works well when project is small, NOT ACCURATE
  • Parametric Estimating: based on some parameters, e.g. the time for producing 1000 component based on that for 1 component * 1000, use an algorithm based on historical data, accuracy depends on the parameters selected, can be used on [a portion of / the entire] project
  • One-Point Estimating: based on expert judgement, but highly unreliable
  • Three-Point Estimating: best (optimistic), most likely (realistic), worst (pessimistic) 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
  • Bottom-Up Estimating: a detailed estimate by decomposing the tasks and derive the estimates based on reliable historical values, most accurate but time-consuming
  • Heuristics: use rule of thumb for estimating
  • standard deviation (sigma value, deviation from mean, to specify the precision of measurement): 1 sigma: 68%, 2 sigma 95%, 3 sigma 99.7%, 6 sigma 99.99%
  • accuracy is the conformance to target value
  • contingency reserve: for known unknowns, owned by PM, may be updated, part of schedule baseline
  • management reserve: for unknown unknowns, owned by management, included in overall schedule requirements
  • update to documents: basis of estimates, assumptions and contingencies
  • activity duration estimate may be in a range, don’t include lags

Develop Schedule

  • the schedule baseline is the approved and signed version of project schedule that is incorporated into the PM plan
  • the schedule is calendar-based taking into accounts holidays/resource availability/vacations
  • vs the time estimate (work effort/level of effort) just describes the man hours / man days
  • 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 affecting another project
  • Negative float: problem with schedule, need schedule 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
    • The float is the highest single value along the critical path, NOT the sum of them
  • 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
  • Forward Pass : compute the early start
  • Backward Pass : compute the late start
  • Fast Tracking : allow overlapping of activities or activities in parallel, included risks/resource overloading
  • Crashing : shorten the activities by adding resources, may result in team burnout
  • 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
  • Network Diagram: bar charts with logical connections
  • 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
  • the Schedule Data includes schedule milestones, schedule activities, activities attributes, and documentation of all assumptions and constraints, alternative schedules and scheduling of contingency reserves
  • the Project Calendars identify working days

Control Schedule

  • measure result, make adjustments, adjust metrics
  • Performance Review includes: Trend Analysis, CPM, CCM, Earned Value Management
  • Change Requests generated are to be assessed in the Perform Integrated Control Process

 

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Edward Chung

Edward Chung aspires to become a full-stack web developer and project manager. In the quest to become a more competent professional, Edward studied for and passed the PMP Certification, ITIL v3 Foundation Certification, PMI-ACP Certification and Zend PHP Certification. Edward shares his certification experience and resources here in the hope of helping others who are pursuing these certification exams to achieve exam success.

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1 Response

  1. Siva says:

    Dear Sir – Could you please send me the mind map diagram that could help remember/pass exam.
    Regards – Siva

November 12, 2013