Project Time Management

  • Processes required to ensure timely completion of the project
  • No consensus concerning differences between activities and tasks
  • Activities seen as composed of tasks –most common usage
  • Other disciplines have tasks composed of activities
Activity Definition: identifying and documenting specific activities to produce project deliverable identified in the WBS
  • Must be defined to meet the project objectives
Activity Definition Inputs
  • WBS – primary input
  • Scope Statement – project justification & project objectives
  • Historical Information 
  • Constraints
  • Assumptions 
Activity Definition Tools & Techniques
  • Decomposition – outputs are expressed as activities rather than deliverables
  • Templates – reuse from previous projects
Activity Definition Outputs
  • Activity List – all to be performed; extension to the WBS and includes description to ensure team members understand work to be performed
  • Supporting Detail – organized as needed and include all assumptions and constraints
  • WBS Updates – identify missing deliverables and clarify deliverable descriptions. WBS updates often called refinements; more likely using new technologies in project 
Activity Sequencing – identifying and documenting interactive dependencies among activities.  Support later development of a realistic schedule
  • Project Management software often used
Activity Sequencing Inputs:
  • Activity List
  • Product Description – product characteristics often affect activity sequencing 
  • Mandatory Sequencing – physical limitations, hard logic, prototypes needed; inherent in nature of work being done
  • Discretionary Dependencies – defined by project management team; “best practices” or unusual aspects of project – soft logic, preferred logic, preferential logic
  • External Dependencies – relationship between project activities and non-project activities  (company policies, procurement, etc.)
  • Constraints
  • Assumptions
Network Diagrams
  • Shows how the project tasks will flow from beginning to end
  • Proves how long the project will take to complete
  • Takes project tasks from low levels of WBS and placing them into their order of completion (beginning to end)
Activity Sequencing Tools & Techniques
  • Precedence Diagramming Method (PDM) – constructing network diagram using nodes to represent activities and arrows to indicate dependencies; also called Activity On Node (AON)
  • Most project management software uses
  • Includes 4 types of dependencies:
    • Finish to Start – “from” activity must finish before “to” activity can begin; most commonly used 
    • Finish to Finish – “from” activity must finish before the next may finish
    • Start to Start – “from” activity must start before next  “to” activity can start
    • Start to Finish – task must start before  next activity can finish
  • Use caution with last 3 techniques  - logical relationships often not consistently implemented with project management software
  • Arrow Diagramming Method (ADM) – uses arrows to represent activities and connecting at nodes to illustrate dependencies
    • Also called Activity On Arrow (AOA)
    • Only uses finish to start dependencies
    • PERT and CPM only can be drawn using AOA
  • Conditional diagramming methods
    • GERT (Graphical Evaluation and Review Technique)
    • System Dynamic Models
    • Allow for non-sequential activities (loops) or conditional branches – not provided by PDM or ADM methods
  • Network Templates – standardized networks can be used. Composed of subnets, or fragnets
    • Subnets are several nearly identical portions of a network (floors on a building, clinical trials, program modules)
    • Useful for several identical processes (clinical trials, programming modules).
Activity Sequencing Outputs:
  • Project Network Diagram – schematic display of project activities and relationships (dependencies). Should be accompanied by a summary narrative that describes the diagram approach
  • Activity List Updates
Activity Duration Estimating
  • Involves assessing number of work periods needed to complete identified activities
  •  Requires consideration of elapsed time, calendars, weekends, and day of week work starts
Activity Duration Estimating Inputs:
  • Activity Lists
  • Constraints
  • Assumptions
  • Resource Requirements – amount of labor assigned to activity
  • Resource Capabilities – human and material resources, expertise
  • Historical Information
    • Project Files, or records of previous project results
    • Commercial Duration Estimates – useful when durations are not driven by actual work (approval periods, material resources)
    • Project Team Knowledge
Activity Duration Estimating Tools & Techniques
  • Expert Judgment – guided by historical information should be used whenever possible; high risk without expertise avail.
  • Simulation – using different sets of assumptions (Monte Carlo Analysis) to drive multiple durations
  • Analogous Estimating – “top down estimating” – use actual, similar, previous known durations as basis for future activity duration.  Used when limited knowledge is available. Form of expert judgment
Activity Duration Outputs:
  • Activity Duration Estimates – quantitative assessments of work periods to complete an activity.  Should indicate a range +/- of possible results
  • Basis of Estimates – all assumptions should be documented
  • Activity List Updates 
Schedule Development
  • Determining start and finish dates for project activities
  • Without realistic dates, project unlikely to be finished as scheduled
  • Schedule development process often iterates as more information becomes available (process inputs)
Schedule Development Inputs:
  • Project Network Diagram
  • Activity Duration Estimates
  • Resource Requirements
  • Resource Pool Description – availability patterns; shared resources are highly variable
  • Calendars – define eligible work periods
  • Project Calendars affect all resources
    • Resource Calendars – affect specific resource pools or individuals
  • Constraints
    • Imposed Dates – may be required
    • Key events or milestones – are initially requested and become expected during project
  • Assumptions
  • Lead and Lag Time – dependencies may specify time in order to satisfy relationship (example – 2 weeks to receive order)
Schedule Development Tools & Techniques
  • Mathematical Analysis – calculating theoretical early/late finish and start dates without regard for resource pool limitations; indicate time periods which activity should be scheduled given resource limits and other constraints:
    • Critical Path Method (CPM) – single early/late start and finish date for all activities. Based on specified, sequential network and single duration estimate. Calculates float to determine flexibility
    • Graphical Evaluation and Review Technique (GERT) – probabilistic treatment of network and activity duration estimates 
    • Program Evaluation and Review Technique (PERT)- sequential network and weighted average duration  to calculate project duration – differs from CPM by using mean (expected value) instead of most-likely estimate in CPM  
  • Critical Path Method: refers to estimating based on one time estimate per activity
    • One time estimate per task (Most Likely)
    • Emphasis on controlling cost and leaving schedule flexible
    • Drawn using AOA diagrams
    • Can have dummy task
  • PERT (Program Review and Estimating Technique)
    • 3 Time estimates per activity 
      • Optimistic
      • Pessimistic
      • Most Likely
    • Emphasis on meeting schedule, flexibility with costs
    • Drawn on AOA diagrams
    • Can have dummy tasks
  • Monte Carlo Analysis
    • Uses a computer with PERT values and network diagram
    • Tells
      • Probability of completing a project on any specific day
      • Probability of completing a project for any specific amount of cost
      • Probability of any task actually being on the critical path
      • Overall Project Risk
    • Suggests that Monte Carlo simulation will create a project duration that is closer to reality than CPM or PERT
  • Duration Compression – look to shorten project schedule without affecting scope
    • Crashing – cost and schedule trade-offs to determine greatest amount of compression for least incremental cost – often results in higher costs
    • Fast Tracking – performing activities in parallel that normally would be sequenced – often results in re-work and usually increases risk
  • Simulation
  • Resource Leveling Heuristics – leveling resources that apply to critical path activities a.k.a. “resource constrained scheduling” – when limitation on quantity of available resources; sometimes called “Resource Based Method” – often increases project duration
  • Project Management Software
  • Project Manger’s role
    • Provide the team with the necessary information to properly estimate the task
    • Complete a sanity check of the estimate
    • Formulate a reserve
  • Project Team should be involved; determine task estimates
    • Historical Records
    • Guesses
    • Actual Costs 
    • Benchmarks
    • CPM and PERT
  • Critical Path Method: longest path through a network diagram and determines the earliest completion of the project
  • Proves how long the project will take
  • Indicates tasks that need most monitoring
  • Almost always have no slack
Schedule Development Outputs:
  • Project Schedule – includes planned start and finish dates for each activity; remains preliminary until resources assignments are approved.  Usually in following formats:
    • Project Network Diagrams (with date information added) – show logical and critical path activities
    • Bar or Gantt charts – activity start and end dates, expected durations
    • Milestone Charts – identifies key deliverables and interfaces 
    • Time-scaled network diagrams – blend of project network and bar charts
  • Supporting Detail – all assumptions and constraints.  May also include:
    • Resource requirement by time period (resource histogram)
    • Alternative schedules (best/worst case)
    • Schedule reserve/risk assessments
  • Schedule Management Plan – how updates are managed
  • Resource requirement updates – leveling and activity impact

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