Project Time Management Ashima Wadhwa

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

Schedule Development Inputs (continued): – 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 Monte Carlo Analysis

Mathematical Analysis – 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

Mathematical Analysis – 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 – 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

Schedule Development Tools & Techniques Schedule Development Tools & Techniques (continued) – 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

Schedule Development Tools & Techniques Schedule Development Tools & Techniques (continued) – 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

Chapter 6 – Project Time Management Schedule Development Tools & Techniques (continued) – 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: – 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

Chapter 6 – Project Time Management Schedule Development Outputs (continued): – 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

Chapter 6 – Project Time Management Schedule Control: – Influencing factors which create schedule changes to ensure changes are beneficial – Determining that schedule has changed – Managing actual changes as they occur Inputs to Schedule Control – Project Schedule – baseline approved, measure against project performance – Performance Reports – planned dates met, issues – Change Requests – Schedule Management Plan

Chapter 6 – Project Time Management Schedule Control Tools & Techniques – Schedule Change Control System – defines procedures for schedule changes, paperwork, approval, tracking systems – Performance Measurement – assess magnitude of variations to baseline; determine if corrective action is needed – Additional Planning – Project Management Software

Schedule Control Outputs: – Schedule Updates – any modifications, stakeholder notification Revisions change scheduled start and finish dates – generally in response to scope changes. “Re- baselining” may be needed in drastic situations – Corrective Action – re-align performance with project plan – Lessons Learned

Chapter 6 – Project Time Management Key knowledge points not in PMBOK – Need to know manual calculations of network diagrams Created after project charter and WBS (task estimates and dependencies are determined) – Mandatory dependencies (Hard Logic) – inherent in nature of work – Discretionary dependencies (Soft Logic) – based on experience, desire or results – External dependencies – based on needs and desires of organizations outside the project

Chapter 6 – Project Time Management Methods to draw network diagrams – Activity on Node (AON) or Precedence Diagramming Method (PDM) Boxes represent tasks Arrows show task dependencies 4 types of task relationships – Finish to Start (task must finish before next can start) – Finish to Finish (task must finish before next can finish) – Start to Start (task must start before next can start) – Start to Finish (task must start before the next can finish) No dummy tasks used

Chapter 6 – Project Time Management Methods to draw network diagrams – Activity on Arrow (AOA or Arrow Diagramming Method (ADM) Arrows used to represent tasks Only Finish to Start relationships are used May use dummy tasks (show dependencies) PERT and CPM estimating techniques can only be drawn using AOA – CPM (Critical Path Method) – estimating based on one time estimate per activity (the most likely time estimate) » Emphasizes controlling cost and allowing schedule flexibility » Can have dummy tasks

Chapter 6 – Project Time Management Methods to draw network diagrams – Activity on Arrow (AOA or Arrow Diagramming Method (ADM) continued: PERT (Program Evaluation and Review technique) – 3 time estimates per activity: Optimistic (O), Most Likely (M), Pessimistic (P) – Emphasizes meeting schedule, flexibility with cost – Can have dummy tasks

Chapter 6 – Project Time Management Methods to draw network diagrams – PERT (Program Evaluation and Review technique) – Estimating based on 3 formulas: PERT Duration: (P + 4M + O)/6 Standard Task Deviation: (P – O)/6 Task Variance: Total project estimate: – Add up all Optimistic, Most Likely and Pessimistic values of the critical path tasks and apply P + 4M + O/6 Total project variance (+/-): – Add up the individual task variances and take the square root of the value. Use the value as a +/- figure to compute the Optimistic and Pessimistic values. The total project estimate will serve as the basis. [ P – O ] 2 6

Chapter 6 – Project Time Management Monte Carlo Simulation: – Uses a computer with PERT values (P, M, O) and a network diagram but does not use the PERT formula – Indicates Probability of completing project on a specific day Probability of completing project for any specific amount of cost Probability of any task actually being on critical path Overall project risk

Chapter 6 – Project Time Management Estimating techniques in general: – Should be performed by entire project team Project manager needs to provide information to allow team to create estimates; sanity check; formulate reserve – Estimates are: Guesses, Historical Records, Actual Costs, Benchmarks, CPM, PERT – Critical paths determines the earliest completion date and identifies tasks that need monitoring – Can be obtained by CPM, PERT and Monte Carlo estimating techniques

Chapter 6 – Project Time Management Key Definitions: – Slack (Float): the amount of time a task can be delayed without delaying the entire project. Tasks on critical path have no slack. Slack is calculated by the difference between Early Start and Late Start of a task – Free Slack (Float): the amount of time a task can be delayed without delaying the early start date of its successor – Total Slack (Float): the amount of time a task can be delayed without delaying the project completion date – Lag: inserted waiting time between tasks

Chapter 6 – Project Time Management General Comments: – Projects can have more than 1 critical path (increases risk) and can involve dummy tasks – Negative float indicates that you are behind – Resource Leveling involves possibly letting schedule and cost slip – Heuristics – just means “rule of thumb” e.g. 80/20 rule – Schedules are calendar based – makes this different than a time estimate Bar Chart a.k.a. Gantt chart (track progress, report to entire team including stakeholders, control tool) Network Diagram (to show task inter-dependencies, show project organization, basis for project control) Milestone chart (report to Senior management, shows major events)

General Comments: – To shorten project schedule examine the critical path Crashing – add more resources to the critical path tasks – Usually results in increased cost Fast Tracking – performing tasks in parallel – Can result in re-work and increased risk – Best to select method that has least impact on the project (is the importance on cost, risk or schedule?)

Chapter 6 – Project Time Management General Comments: – Bar (Gantt) Charts Weak Planning Tool, effective progress and reporting tool Does not show interdependencies of tasks Does not help organize the project more effectively – Network Diagrams (PERT, CPM, PDM) Shows task interdependencies Aids in effectively planning and organizing work Provides a basis for project control – Milestone Charts Only shows major events Good for reporting to management and customer – Flow Charts Depicts workflow and not commonly used for project management

Chapter 6 – Project Time Management General Comments: – Free Slack (Float) – amount of time a task can be delayed without delaying the early start date of its successor – Total Slack (Float) – amount of time a task can be delayed without delaying the project completion date Lag – inserted waiting time between tasks Resource Leveling – level peaks of resource usage; stable number of resources – allows schedule and cost slip in favor of leveling resources Heuristic – rule of thumb (80/20 rule)