Time Management Week 7 - Learning Objectives You should be able to: n List and describe the processes, activities, inputs, and outputs in time management n Create and interpret a network diagram n Create and interpret a GANTT chart n Define and use: CPM, critical path and time, slack time, crash time, fast-tracking

Time Management Issues n Frequent source of project failure –Often used as a success measure n Frequent source of project conflict n Time / cost / scope tradeoffs n Less negotiable, least flexibility n Stakeholder involvement –communication and commitment

Time Management Processes n Define Activities –further defines scope n Sequence Activities –further defines time n Estimate Duration –further defines cost n Develop Schedule n Control Schedule

Activity n Element of work - on WBS –cost –duration –resources n “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 n Steps needed to produce deliverables n Inputs: –WBS, Scope, historical data, constraints, assumptions n Outputs: –Activity list, descriptions, supporting detail, updates to WBS –complete understanding of work involved

Sequencing Activities n Identifying dependencies –relationships between activities n Mandatory dependencies –technical, defined by type of work n Discretionary dependencies –defined by project team n External dependencies –relationships to non-project activities

Activity Sequencing Tools n Network diagrams –schematic display of activities and dependencies –activity on arrow (AOA or ADM) n Precedence diagramming –activity on node (AON or PDM)

A (20) C (10) I (18) F (14) E (10) J (8) D (15) B (20) G (4) H (11)

Precedence Diagram (PDM) n Boxes represent activities n 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 n Should involve stakeholders, people doing the work n Inputs: –Activity list, constraints, assumptions –Resource requirements –Resource capabilities (human and materials) –Use historical data, previous projects, experience, simulations n Outputs: duration estimates –quantitative assessments of likely number of work periods required to complete activity

Developing the Schedule n 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 n GANTT charts n CPM: Critical Path Method n PERT: probabilistic time estimation n Simulation

GANTT Chart n shows planned vs. actual progress n multiple tasks on horizontal time scale n easy to read, easy to construct n monitoring and control of progress n requires frequent updating n limited display of dependencies

Components of GANTT Chart n Activities - scheduled and actual n Precedence relationships n Milestones (identifiable points in project) –usually represents reporting requirements –usually corresponds to critical events n Can add budget information n Does not show technical interdependencies n Need network diagram to interpret, control, and compensate for delays

Gantt Chart symbols n Milestone: –diamond n Summary task: –dark bar n Individual task: –light bar n Arrows: –dependencies

CPM Definitions n Activity: uses resources and takes time n Event : result of completing an activity –has identifiable end state at a point in time n Network : combined activities & events in a project n Path: series of connected activities n Critical: activities, events, or paths which, if delayed, will delay project completion n Critical path: sequence of critical activities from start to finish n Node: start or end of an activity n Arrow (Arc): shows path

A, B,4 E,5 F,8 C,6 D,2 5 1 A-C-F = 19 B-E = 9 B-D-F = 14 Critical Path is A-C-F Critical Time 19

n EOT: –earliest occurrence time for event –time required for longest path leading to event n LOT: latest occurrence time for event n EST: earliest starting time for activity n LST: latest starting time for activity n Critical time: shortest time in which the project can be completed n Slack time : difference between earliest and latest start times

A (22) C (10) I (18) F (14) E (10) J (8) D (15) B (20) G (4) H (11)

n What is the critical path? Critical time? –B-F = 34 –B-E-J = 38 –A-D-J = –B-G-I = –C-H-I = n What is the earliest occurrence time of event 6? n What is the latest start time for activity F?

Probabilistic Time Estimation n More realistic, includes uncertainty n Expected completion time –optimistic, pessimistic, most likely times n take weighted average of the 3 times TE = (a + 4m + b)/6 n uncertainty = variance (range of values) n Probability of completion of project in desired time D Z = (D - ì)/(sqrt(ó 2 ì ))

Outputs of Scheduling Process n Date-enhanced project network diagram n GANTT charts, milestone charts n Time-scaled network diagrams –combines GANTT, network diagram n Supporting detail n Schedule management plan

Shortening the Schedule n Duration compression n Crashing: –time/cost tradeoff n Fast tracking: –parallel vs. sequential n 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 n Determining, managing schedule changes n Influencing changes so they are beneficial n Inputs: –schedule, performance reports, change requests, schedule management plan n Outputs: –schedule updates & notification –corrective action to minimize delays –lessons learned

Controlling Schedule Changes n Involve stakeholders –manage expectations –progress meetings –no surprises n Leadership, discipline, negotiation –review draft schedule and add details –realistic estimates –allow for contingencies –empower and incent employees n Proper use of tools