Software Project Management Task Sequencing Activity Sequencing Concepts PERT charts Critical Path Analysis

Project Time Management Processes Project time management involves the processes required to ensure timely completion of a project. Processes include:  Activity definition (your WBS)  Activity sequencing (this topic)  Activity duration estimating (next week) Activity Definition This comes from your WBS  Recall it encompasses the total scope of the project  It is organized by a perspective, or organizing principle What it doesn’t do: Help you plan temporally  You need to know X needs to be done before Y because X may produce a deliverable (or knowledge) required for Y  You may need to ensure you can provide all of the resources (people, technology, etc.) at a given time to ensure success Time Quality Scope CostExpectations

Activity Sequencing Involves developing a more detailed WBS and supporting explanations to understand all the work to be done  An outgrowth of your WBS’ work packages  Initial dependencies should arise What needs to be done before to make data available (flow) What tasks are a “part of” other tasks (decomposition) This is the resulting sequencing of activities to achieve goals Review activities and determine dependencies  Mandatory: inherent in the nature of the work; hard logic Example: Coding must happen before testing  Discretionary: defined by the team; soft logic applied within a process Example: Order in which components are implemented  External: involve relationships between project & non-project activities Example: 3rd party / open source software release  Resource: Multiple projects depend on same resource Example: You have only 1 Oracle-certified DBA but 2 projects

Activity Sequencing Tools for Activity Sequencing  Task networks, PERT charts, Critical Path Analysis Task networks  A graphical representation of tasks  Visualizes tasks, flows, and relationships  Two formats: Activity-on-Arrow (AOA) –Nodes represent Events, Lines represent Tasks Activity-on-Node (AON) –Nodes represent Tasks, Lines dependencies between Tasks AON: START Code Module Write Unit Test Perform Code Review Fix Defects Check-in Code

AOA Example *Taken from Scach 4 th ed. P. 289

Activity Sequencing Temporal Dependencies between Tasks Finish-to-Start (FS)  B cannot start till A finishes  A: Construct fence; B: Paint Fence Start-to-Start (SS)  B cannot start till A starts  A: Pour foundation; B: Level concrete Finish-to-Finish (FF)  B cannot finish till A finishes  A: Add wiring; B: Inspect electrical Start-to-Finish (SF)  B cannot finish till A starts (rare)

Critical Path Method (CPM) CPM is a project network analysis technique used to predict total project duration  A critical path 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  Typically used in conjunction with PERT charts (or also with Activity- Task Analysis, Task Networks, etc.) 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 Course Technology, 1999

Determining the Critical Path Consider the following project network (AOA) diagram. Assume all times are in days. a. How many paths are on this network diagram? b. How long is each path? c. Which is the critical path? d. What is the shortest amount of time needed to complete this project? Course Technology, 1999

Determining the Critical Path Course Technology, 1999 Example (AOA):

More on the Critical Path 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 If one of more activities on the critical path takes longer than planned, the whole project schedule will slip unless corrective action is taken  We will discuss what “corrective actions” are possible with scheduling next week. Course Technology, 1999

PERT Charts Program Evaluation and Review Technique  Network analysis technique used to estimate project duration if there is a high degree of uncertainty about individual activity duration estimates  PERT uses probabilistic time estimates based on using optimistic, most likely, and pessimistic estimates of activity durations Course Technology, 1999 EXAMPLE: