Software Project Planning

Weinberg's Second Law If builders built buildings the way programmers wrote programs: Then the first woodpecker that came along would destroy civilization.

Work Breakdown Structure (WBS) The Work Breakdown Structure (WBS) is a hierarchical definition of the tasks and activities of a project. It normally begins with the highest-level activities and works downward into the individual tasks and components.

Work Breakdown Structure (WBS) The following are properties of a WBS: –The WBS must be a tree structure –Every task and deliverable description must be understandable and unambiguous –Every task must have completion criteria

Properties of a WBS All deliverables (artifacts) must be identified. Positive completion of the sub-tasks must imply completion of the whole task.

Example of a WBS

WBS Example: Eating Breakfast Get eggs from refrigerator Crack eggs Cook eggs Get bread out of breadbox Toast bread Butter bread Get out dinnerware Put food on plate Eat food Clean up dishes

Create a WBS tree Prepare Eggs Make Breakfast Prepare Toast Set Table Clean Up Get Eggs Crack Eggs Cook Eggs Get bread Toast bread Butter bread Eat

Program Evaluation and Review Technique (PERT) Program evaluation and review technique (PERT) is a decision technique that helps group members order the activities that must be completed to implement a decision.

PERT Example: Eating Breakfast Get eggs from refrigerator - 15 Crack eggs - 30 Cook eggs Get bread out of breadbox - 15 Toast bread - 60 Butter bread - 60 Get out dinnerware - 30 Put food on plate - 30 Eat food Clean up dishes - 240

PERT Example: Eating Breakfast Get Eggs Set Table Clean Up Crack Eggs Cook Eggs Get bread Toast bread Butter bread Eat Done 1.Find the earliest completion time (ECT) for each node. 2.Find the latest completion time (LCT) for each node. 3.Find the slack time (ST) for each node 4.Find the where the slack time = 0. These are the critical paths. To find the critical paths you must: Critical paths are paths through the PERT graph that must be done on time to stay on track

PERT Example: Eating Breakfast Get Eggs Set Table Clean Up Crack Eggs Cook Eggs Get bread Toast bread Butter bread Eat Done 1.Find the earliest completion time (ECT) for each node. 2.Find the latest completion time (LCT) for each node. 3.Find the slack time (ST) for each node 4.Find the paths where slack time = 0 These are the critical paths ECT=15ECT=45 ECT=15 ECT=75 ECT=345 ECT=825 ECT=1065 LCT=15LCT=45 LCT=225 LCT=285 LCT=345 LCT=825 LCT=1065 ST=0 ST=210 ECT=135 LCT=345 ST=210 ECT=30 LCT=345 ST=315

Thinking ahead You should start thinking of a WBS tree and PERT graph for your project This will be part of your project schedule assignment