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Time Management Week 7 - Learning Objectives. You should be able to: List and describe the processes, activities, inputs, and outputs in time management Create and interpret a network diagram Create and interpret a GANTT chart
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Time Management Week 7 - Learning Objectives You should be able to: • List and describe the processes, activities, inputs, and outputs in time management • Create and interpret a network diagram • Create and interpret a GANTT chart • Define and use: CPM, critical path and time, slack time, crash time, fast-tracking
Time Management Issues • Frequent source of project failure • Often used as a success measure • Frequent source of project conflict • Time / cost / scope tradeoffs • Less negotiable, least flexibility • Stakeholder involvement • communication and commitment
Time Management Processes • Define Activities • further defines scope • Sequence Activities • further defines time • EstimateDuration • further defines cost • Develop Schedule • Control Schedule
Activity • Element of work - on WBS • cost • duration • resources • “Tasks” vs. “activities”? • Doesn’t matter, as long as the work to be done is described accurately and understood by those who must do the work
Define Activities • Steps needed to produce deliverables • Inputs: • WBS, Scope, historical data, constraints, assumptions • Outputs: • Activity list, descriptions, supporting detail, updates to WBS • complete understanding of work involved
Sequencing Activities • Identifying dependencies • relationships between activities • Mandatory dependencies • technical, defined by type of work • Discretionary dependencies • defined by project team • External dependencies • relationships to non-project activities
Activity Sequencing Tools • Network diagrams • schematic display of activities and dependencies • activity on arrow (AOA or ADM) • Precedence diagramming • activity on node (AON or PDM)
D (15) 6 2 J (8) A (20) E (10) F (14) B (20) 3 7 1 G (4) I (18) C (10) 4 5 H (11)
Precedence Diagram (PDM) • Boxes represent activities • Types of dependencies: • finish-to-start • start-to-start (can be parallel) • finish-to-finish (can be parallel) • start-to-finish (rarely used)
Estimating Duration • Should involve stakeholders, people doing the work • Inputs: • Activity list, constraints, assumptions • Resource requirements • Resource capabilities (human and materials) • Use historical data, previous projects, experience, simulations • Outputs: duration estimates • quantitative assessments of likely number of work periods required tocomplete activity
Developing the Schedule • Inputs to schedule development: • project network diagram • activity duration estimates • resource requirements • resource pool description • calendars (project and resource) • constraints, assumptions, leads and lags
Scheduling Tools • GANTT charts • CPM: Critical Path Method • PERT: probabilistic time estimation • Simulation
GANTT Chart • shows planned vs. actual progress • multiple tasks on horizontal time scale • easy to read, easy to construct • monitoring and control of progress • requires frequent updating • limited display of dependencies
Components of GANTT Chart • Activities - scheduled and actual • Precedence relationships • Milestones(identifiable points in project) • usually represents reporting requirements • usually corresponds to critical events • Can add budget information • Does not show technical interdependencies • Need network diagram to interpret, control, and compensate for delays
Gantt Chart symbols • Milestone: • diamond • Summary task: • dark bar • Individual task: • light bar • Arrows: • dependencies
CPM Definitions • Activity: uses resources and takes time • Event: result of completing an activity • has identifiable end state at a point in time • Network: combined activities & events in a project • Path: series of connected activities • Critical: activities, events, or paths which, if delayed, will delay project completion • Critical path: sequence of critical activities from start to finish • Node: start or end of an activity • Arrow (Arc): shows path
A-C-F = 19 B-E = 9 B-D-F = 14 Critical Path is A-C-F Critical Time 19 C,6 2 4 F,8 A,5 1 D,2 5 B,4 3 E,5
EOT: • earliest occurrence time for event • time required for longest path leading to event • LOT: latest occurrence time for event • EST: earliest starting time for activity • LST: latest starting time for activity • Critical time: shortest time in which the project can be completed • Slack time: difference between earliest and latest start times
D (15) 6 2 J (8) A (22) E (10) F (14) B (20) 3 7 1 G (4) I (18) C (10) 4 5 H (11)
What is the critical path? Critical time? • B-F = 34 • B-E-J = 38 • A-D-J = • B-G-I = • C-H-I = • What is the earliest occurrence time of event 6? • What is the latest start time for activity F?
Probabilistic Time Estimation • More realistic, includes uncertainty • Expected completion time • optimistic, pessimistic, most likely times • take weighted average of the 3 times TE = (a + 4m + b)/6 • uncertainty = variance (range of values) • Probability of completion of project in desired time D Z = (D - ì)/(sqrt(ó2 ì))
Outputs of Scheduling Process • Date-enhanced project network diagram • GANTT charts, milestone charts • Time-scaled network diagrams • combines GANTT, network diagram • Supporting detail • Schedule management plan
Shortening the Schedule • Duration compression • Crashing: • time/cost tradeoff • Fast tracking: • parallel vs. sequential • Resource loading and leveling: • more even distribution of resource usage
Slope =(crash cost - normal cost ) (crash time - normal time) = cost per day of crashing activity
Schedule Control • Determining, managing schedule changes • Influencing changes so they are beneficial • Inputs: • schedule, performance reports, change requests, schedule management plan • Outputs: • schedule updates & notification • corrective action to minimize delays • lessons learned
Controlling Schedule Changes • Involve stakeholders • manage expectations • progress meetings • no surprises • Leadership, discipline, negotiation • review draft schedule and add details • realistic estimates • allow for contingencies • empower and incent employees • Proper use of tools