Chapter 6

PERT weighted Average

(Optimistic Time+[4∗most likely time]+pessimistic time)/6

Process for creating AOA diagrams

1. Find all of the activities that start at node 1. draw their finish nodes and draw arrows between node 1 and those finish nodes. Put the activity letter or name and duration estimate on the associated arrow 2. Contining drawing the network diagram, working from left to right. Look for bursts and merges. i. Bursts occur when a single node is followed by two or more activities ii. A merge occurs when two or more nodes precede a single node 3. Continue drawing the project network diagram until all activities are included on the diagram that have dependencies As a rule of thumb, all arrowheads should face toward the right, and no arrows should cross on an AOA network diagram

Project Time Management Processes

Planning schedule Management Defining Activities Sequencing activities Estimating activity resources estimating activity durations Developing Schdule Controlling the schedule

• Buffers and Critical Chain

○ A buffer is additional time to complete a task ○ Murphy[s law states that if something can go wrong, it will ○ Parkinson's law states that work expands to fill the time allowed ○ In traditional estimates, people often add a buffer to each task and use it if it's needed or not ○ Critical chain scheduling removes buffers from individual tasks and instead creates § A project buffer or additional time added before the project's due date § Feeding buffers or additional time added before tasks on the critical path

• Critical chain scheduling

○ A method of scheduling that considers limited resources when creating a project schedule and includes buffers to protect the project completion date ○ Uses the theory of constraints ○ Attempts to minimize multitasking

Milestones

○ A milestone is a significant event that normally has no duration ○ It often takes several activities and a lot of work to complete a milestone ○ They're useful tools for setting schedule goals and monitoring progress ○ Examples include obtaining customer sign-off on key documents or completion of specific products

Program Evaluation and Review (PERT)

○ A network analysis technique used to estimate project duration when there is a high degree of uncertainty about the individual activity duration estimates ○ PERT uses probabilistic time estimates § Duration estimates based on using optimistic, most likely, and pessimistic estimates of activity durations, or a three-point estimate

More on the critical path

○ A project team at Apple computer put a stuffed gorilla on the top of the cubicle of the person currently managing critical task ○ The critical path is not the one with all the critical activities; it only accounts for time § Remember the example of growing grass being on the critical path for Disney's Animal Kingdom ○ There can be more than one critical path if the lengths of two or more paths are the same ○ The critical path can change as the project progresses

Precedence Diagramming Method

○ Activities are represented by boxes ○ Arrows show relationships between activities ○ More popular than ADM method and used by project management software Better at showing different types of dependencies

• Arrow diagramming method (ADM)

○ Also called activity-on-arrow network diagrams ○ Activities are represented by arrows ○ Nodes or circles are the starting and ending points of activities ○ Can only show finish-to-start dependencies

Defining Activities

○ An activity or task is an element of work normally found on the WBS that has an expected duration, a cost, and resource requirements Activity definition involves developing a more detailed WBS and supporting explanations to understand all the work to be done so you can develop realistic cost and duration estimates

• Activity Lists and Attributes

○ And activity list is a tabulation of activities to be included on a project schedule that includes § The activity name § An activity identifier or number § A brief description of the activity ○ Activity attributes provide more information such as predecessors, successors, logical relationships, leads and lags, resource requirements, constraints, imposed dates, and assumptions related to the activity

Estimating Activity Resources

○ Before estimating activity durations, you must have a good idea of the quantity and type of resources that will be assigned to each activity § Resources are people, equipment, and materials ○ Consider important issues in estimating resources § How difficult will it be to do specific activities on this project? § What is the organization's history in doing similar activities? § Are the required resources available? A resource breakdown structure is a hierarchical structure that identifies the project's resources by category and type

• Critical Path Method (CPM)

○ CPM is a network diagramming technique used to predict total project duration ○ A critical path for a project is the series of activities that determines the earlist time by which the project can be completed ○ The critical path is the longest path throught eh network diagram and has the least amount of slack or float ○ Slack or float is the amount of time an activity may be delayed without delayinh a succeeding activity or the project finish date

Agile and Time Management

○ Core values of the manifesto for Agile Software development are § Customer collaboration over contract negotiation § Responding to change over following a plan ○ The product owner defines and prioritizes the work to be done within a sprint, so collaboration and time management are designed into the process ○ Teams focus on producing a useful product in a specified timeframe with strong customer input ○ Don't emphasize defining all the work before scheduling it

• Activity Duration Estimating

○ Duration § Includes the actual amount of time worked on an activity plus elapsed time ○ Effort § The number of workdays or work hours required to complete a task ○ Effort does not normally equal duration ○ Pepole doing the work should help create estimates, and an expert should review them

• PDM Task Dependency Types

○ Finish-to-start § Task (B) cannot start until task (A) finishes ○ Start-to-start § Task (B) cannot start until task (A) starts ○ Finish-to-finish § Task (B) cannot finish until task (A) finishes ○ Start-to-finish Task (B) cannot finish until task (A) starts

Calculating the Critical path

○ First develop a good network diagram ○ Add the duration estimates for all activities on each path through the network diagram ○ The longest path is the critical path ○ If one or more of the activities on the critical path takes longer than planned, the whole project schedule will slip unless the project manager takes corrective action

Reality Checks on Scheduling

○ First review the draft schedule or estimated completion date in the project charter ○ Perpare a more detailed schedule with the project team ○ Make sure the schedule is realistic and followed ○ Alert top management well in advance if there are schedule problems

Using critical path analysis to make schedule trade-offs

○ Free slack or free float is the amount of time an activity can be delayed without delaying the early start of any immediately following activities ○ Total slack or total float is the amount of time an activity may be delayed from its early start without delaying the planned project finish date ○ A forward pass through the network diagram determines the early start and finish dates ○ A backward pass determines the late start and finish dates

• Controlling the schedule

○ Goals are to know the status of the schedule, influence factors that cause schedule changes, dtermine that the schedule has changed, and manage changes when they occur ○ Tools and techniques include § Progress reports § A schedule change control system § Project management software including scheudle comparison charts like the tracking Gantt chart § Variance analysis, such as analyzing float or slack § Performance management, such as earned value

• Media Snapshot

○ In contrast to the 2002 Salt Lake City Winter Olympic Games, planning and scheduling was very different for the 2004 Athens Summer and the 2014 Sochi Winter Olympics ○ Many articles were written before the opening ceremonies in Athens predicting that the facilities would not be ready in time...the Greeks even made fun of critics by having constructions workers pretend to still be working as the ceremonies began...but the games cost more than twice the planned budget The 2014 Winter Olympic Games in Sochi, suffered even greater financial loss and were the most expensive games in history

• Three-point estimates

○ Instead of providing activity estimates as a discrete number, such as four weeks, its often helpful to create a three point estimate § An estimate that includes an optimistic, most likely, and pessimistic estimate, such as three weeks for the optimistic, four weeks for the most likely, and five weeks for the pessimistic estimate ○ Three-point estimates are needed for PERT and Monte Carlo simulations

• Sequencing Activities

○ Involves reviewing activities and determining dependencies ○ A dependency or relationship is the sequencing of project activities or tasks You must determine dependencies in order to use critical path analysis

• Importance of updating critical path data

○ It is important to update project schedule information to meet time goals for a project ○ The critical path may change as you enter actual start and finish dates ○ If you know the project completion date will slip, negotiate with the project sponsor

• Importance of Project Schedules

○ Managers often cite delivering projects on time as one of their biggest challenges ○ Time has the least amount of flexibility; it passes no matter what happens on a project Schedule issues are the main reason for conflicts on projects, especially during the second half of projects

• Three types of dependencies

○ Mandatory dependencies § Inherent in the nature of the work being performed on a project, sometimes referred to as hard logic ○ Discretionary dependencies § Defined by the project team § Sometimes referred to as soft logic and should be used with care since they may limit later scheduling options ○ External Dependencies § Involve relationships between project and non-project activities

• Adding Milestones to Gantt Charts

○ Many people like to focus on meeting milestones, especially for large projects ○ Milestones emphasize important events or accomplishments on projects ○ Normally create milestone by entering tasks with a zero duration, or you can mark any task as a milestone

SMART Criteria

○ Milestones should be § Specific § Measurable § Assignable § Realistic § Time-framed

• Network Diagrams

○ Network diagrams are the preferred technique for showing activity sequencing ○ A network diagram is a schematic display of the logical relationships among, or sequencing of, project activities ○ Two main formats are the arrow and precedence diagramming methods

Individual Work styles and cultural differences cause schedule conflicts

○ One dimension of the meyers-briggs type indicator focuses on peoples' attitudes toward structure and deadline ○ Some people prefer to follow schedules and meet deadlines while others do not ○ Difference cultures and even entire countries have different attitudes about schedules

Schedule Control Suggestions

○ Perform reality checks on schedules ○ Allow for contingencies ○ Don't plan for everyone to work at 100% capacity all the time ○ Hold progress meetings with stakeholders and be clear and honest in communicating schedule issues

• Gantt Charts

○ Provide a standard format for displaying project schedule information by listing project activities and their corresponding start and finish dates in a calendar format ○ Symbols include: § A black diamond: a milestone § Thick black bars: summary tasks § Lighter horizontal bars: durations of tasks § Arrows: dependencies between tasks

Three main techniques for shortening schedules

○ Shortening durations of critical activities/tasks by adding more resources or changing their scope ○ Crashing activities by obtaining the greatest amoung of schedule compression for the least incremental cost ○ Fast tracking activities by doing them in parallel or overlapping them

• Planning Schedule Management

○ The project team uses expert judgement, analytical techniques, and meetings to develop the schedule management plan ○ A schedule management plan includes § Project schedule model development § The scheduling methodology § Level of accuracy and units of measure § Control Thresholds § Rules of performance measurement § Reporting formats Process description

• Developing the Schedule

○ Uses results of the other time management processes to determine the start and end date of the project ○ Ultimate goal is to create a realistic project schedule that provides a basis for monitoring project progress for the time dimension of the project ○ Important tools and techniques include Gantt charts, critical path analysis, and critical chain scheduling, and PERT analysis