Notes

Outline

Chapter 5: Project Time Management

Importance of Project Schedules Managers often cite delivering projects on time as one of their biggest challenges Average time overrun from 1995 CHAOS report was 222%; improved to 63% in 2001 study Time has the least amount of flexibility; it passes no matter what Schedule issues are the main reason for conflicts on projects, especially during the second half of projects

Figure 5-1. Conflict Intensity Over the Life of a Project

Project Time Management Processes Project time management involves the processes required to ensure timely completion of a project.  Processes include: Activity definition Activity sequencing Activity duration estimating Schedule development Schedule control

Where Do Schedules Come From? Defining Activities Project schedules grow out of the basic document that initiate a project Project charter includes start and end dates and budget information Scope statement and WBS help define what will be done Activity definition involves developing a more detailed WBS and supporting explanations to understand all the work to be done

Activity Sequencing Involves reviewing activities and determining dependencies Mandatory dependencies: inherent in the nature of the work; hard logic Discretionary dependencies: defined by the project team; soft logic External dependencies: involve relationships between project and non-project activities You must determine dependencies in order to use critical path analysis

Project Network Diagrams Project network diagrams are the preferred technique for showing activity sequencing A project network diagram is a schematic display of the logical relationships among, or sequencing of, project activities

Figure 5-2. Sample Activity-on-Arrow (AOA) Network Diagram for Project X

Arrow Diagramming Method (ADM) Also called activity-on-arrow (AOA) project 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

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. Continuing drawing the network diagram, working from left to right.  Look for bursts and merges.  Bursts occur when a single node is followed by two or more activities.  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 4. As a rule of thumb, all arrowheads should face toward the right, and no arrows should cross on an AOA network diagram

Precedence Diagramming Method (PDM) 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

Figure 5-3. Task Dependency Types

Figure 5-4. Sample Precedence Diagramming Method (PDM) Network Diagram for Project X

Activity Duration Estimating After defining activities and determining their sequence, the next step in time management is duration estimating Duration includes the actual amount of time worked on an activity plus elapsed time People doing the work should help create estimates, and an expert should review them

Schedule Development Schedule development uses results of the other time management processes to determine the start and end date of the project and its activities 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, PERT analysis, critical path analysis, and critical chain scheduling

Gantt Charts 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: milestones or significant events on a project with zero duration Thick black bars: summary tasks Lighter horizontal bars: tasks Arrows: dependencies between tasks

Figure 5-5. Gantt Chart for Project X

Figure 5-6. Gantt Chart for Software Launch Project

Figure 5-7. Sample Tracking Gantt Chart

Critical Path Method (CPM) CPM is a project network analysis technique used to predict total project duration A critical path for a project is the series of activities that determines the earliest time by which the project can be completed The critical path is the longest path through the network diagram and has the least amount of slack or float

Finding the Critical Path First develop a good project network diagram Add the durations for all activities on each path through the project network diagram The longest path is the critical path

Simple Example of Determining the Critical Path Consider the following project network diagram.  Assume all times are in days.

Figure 5-8.  Determining the Critical Path for Project X

More on the Critical Path If one of more activities on the critical path takes longer than planned, the whole project schedule will slip unless corrective action is taken Misconceptions: The critical path is not the one with all the critical activities; it only accounts for time 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

Using Critical Path Analysis to Make Schedule Trade-offs Knowing the critical path helps you 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

Table 5-1. Free and Total Float or Slack for Project X

Techniques for Shortening a Project Schedule Shortening durations of critical tasks for adding more resources or changing their scope Crashing tasks by obtaining the greatest amount of schedule compression for the least incremental cost Fast tracking tasks by doing them in parallel or overlapping them

Many Horror Stories Related to Project Schedules See “What Went Wrong?” example about the National Insurance Recording System Creating realistic schedules and sticking to them is a key challenge of project management

Importance of Updating Critical Path Data It is important to update project schedule information 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

Critical Chain Scheduling Technique that addresses the challenge of meeting or beating project finish dates and an application of the Theory of Constraints (TOC) Developed by Eliyahu Goldratt in his books The Goal and Critical Chain Critical chain scheduling is a method of scheduling that takes limited resources into account when creating a project schedule and includes buffers to protect the project completion date Critical chain scheduling assumes resources do not multitask because it often delays task completions and increases total durations

Multitasking Example

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, and Parkinson’s Law states that work expands to fill the time allowed.  In traditional estimates, people often add a buffer and use it if it’s needed or not Critical chain schedule removes buffers from individual tasks and instead creates A project buffer, which is additional time added before the project’s due date Feeding buffers, which are addition time added before tasks on the critical path

Figure 5-10. Example of Critical Chain Scheduling

Program Evaluation and Review Technique (PERT) PERT is 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 based on using optimistic, most likely, and pessimistic estimates of activity durations

PERT Formula and Example PERT weighted average formula: optimistic time + 4X most likely time + pessimistic time 6 Example: PERT weighted average =  8 workdays + 4 X 10 workdays + 24 workdays = 12 days 6 where 8 = optimistic time, 10 = most likely time, and 24 = pessimistic time

Controlling Changes to the Project Schedule 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

Working with People Issues Strong leadership helps projects succeed more than good PERT charts Project managers should use empowerment incentives discipline negotiation

What Went Right?

Using Software to Assist in Time Management Software for facilitating communications helps people exchange schedule-related information Decision support models help analyze trade-offs that can be made Project management software can help in various time management areas

Table 5-2. Project 98 Features Related to Project Time Management

Words of Caution on Using Project Management Software Many people misuse project management software because they don’t understand important concepts and have not had good training You must enter dependencies to have dates adjust automatically and to determine the critical path You must enter actual schedule information to compare planned and actual progress