Software Project Planning Project Planning, Scheduling, and Monitoring Jalote-2002, etc.

Introduction Effectively schedule, allocate, use, and replace resources to achieve goals Master schedule is the basic tool and main output of planning Project control is based on comparing the progress with schedule Planning and scheduling are dynamic

Reluctance to Planning Takes too much time and cost Preventive action Long-term payoff is greater than short-term cost Too tedious (mental activity) “Thinker” and “doer” Ego (shoot from the hip) Not realistic

Effective Schedule Understandable Sufficiently detailed Highlighting critical tasks Flexible Based on reliable estimates Conform to available resources Compatible with other related projects

Scheduling Total schedule is a function of total effort and (flexible) resource allocation issues. Simple estimate of schedule: S = a * Eb “Square root” rule of thumb: Proposed schedule and number of resources should be around the square root of total effort in person-month. Dependencies have to be considered too.

Scheduling Next step: milestones, per-phase resource allocation, and detailed scheduling Rayleigh curve and peak time size (PTS) Peak usually happens at “build” phases after “design” and before “test” In detailed schedule, low level tasks should need a few days and one person Slack time Due to fixed resource allocation Used for training, documentation, … Schedule and effort distributions are different Design and test usually have larger percentage of schedule compared to effort Schedule: 40-40-20%, manpower ratio: 1,2,1

Developing the Schedule Defining objectives Attainable, definitive, quantifiable, with specific duration Breaking down the work Sequencing the activities Estimating the activity costs and durations Reconciling with time constraints Reconciling with resource constraints Reviewing

Work Breakdown Structure WBS is a hierarchical representation of a process or product or both (hybrid). WBS can be shown in a tree graph or as an indented list A decimal numbering to label the elements e.g. 4.1.2 is the 2nd element of the 1st element of the 4th 4th 1st 2nd

Tree Graph WBS for ATC ATC System Project Management SW Eng. Operations Product Assur. Req. Eng. Design Coding Test QA V&V Preliminary Detailed

Indented List WBS for ATC 0.0 Air Traffic Control (ATC) System 1.0 Project Management 2.0 Software Engineering 2.1 Requirement Engineering 2.2 Design 2.3 Coding 2.4 Test 3.0 Operations 4.0 Product Assurance 4.1 Quality Assurance 4.2 Verification and Validation

Notes on WBS “Rolling wave” approach First top levels Gradual completion Keep partitioning into 72 elements WBS dictionary Make sure about numbering scheme Top-level zero or one, … Work package specification for lowest level entries (info, completion, …)

Sequencing Scheduled Activities Interrelationship among activities Milestones and Gantt charts are most common Gantt chart also shows the relationship between work load and time Full-wall method gives a global view Precedence networks are used for larger projects Critical Path Method (CPM) Program Evaluation and Review Technique

Milestone Chart Simplest scheduling method Small projects or summary of larger ones Ease and minimal cost No interrelationships exhibited Only completion dates Not enough feedback

Gantt Chart Gantt or Bar chart used more frequently than others Suitable for projects with less than 25 activities Graphical display of start/end times Shows overlapping activities easily CPM or PERT are translated to Gantt sometimes For estimation of resource and budget vs. time

Gantt Example - 1

Gantt Example - 2

Precedence Networks Network is a graphical representation of sequential relationship between: Activities Events Critical Path Method (CPM) Activity-based Program Evaluation and Review Technique (PERT) Event-based

CPM/PERT AOA (activity-on-arc) AON (activity-on-node) CPM PERT Nodes are “events” and arcs are “activities” leading to them AON (activity-on-node) Nodes are “activities” and arcs show the sequence/order CPM Labels and focuses on activities Usually AOA e.g. construction projects PERT Labels and focuses on events Almost always AOA More complicated projects

CPM/PERT Graph

Critical Path

Activity Slack Maximum time that an activity can be delayed without delaying the entire project Zero for those on critical path S = LS - ES or S = LF – EF LS is Latest and ES is Earliest Start time for activity (or source node) LF is Latest and EF is Earliest Finish time Earliest times calculated using “forward pass” ESj = maxi {(ESi + time for activity ai,j)} , i and j are nodes ES for last node is “project deadline” Latest times calculated using “backward pass” What’s the latest time for each node, keeping the deadline?

Probabilistic PERT No unique estimate for time/effort Optimistic, a Realistic, m Pessimistic, b mean=((2m+(a+b)/2)/3) sigma2=((b-a)/6)2 Central Limit Theorem Sum of the activity times on the critical path is a random variable with a normal distribution, its mean and variance the sum of the means and variances of the activities on the critical path

When CPM/PERT? Sequential Interrelated Ordered Without interruption Well-defined CPM Uncertain PERT (allows probability for time estimates)

Format for Project Plan - 1 Title page Signature page Change history Preface Table of contents List of figures List of tables

Format for Project Plan - 2 1- Overview Summary Purpose, scope, objectives Assumptions and constraints Deliverables Schedule and budget summary Evolution of plan 2- References 3- Definitions

Format for Project Plan - 3 4- Project organization External interface Internal structure Roles and responsibilities 5- Managerial process plans Estimation (cost, schedule) Work (activities, resource and budget allocation) Control (quality, metrics, …) Risk management

Format for Project Plan - 4 6- Technical process plans Process model Methods, tools Acceptance plan 7- Supporting process plans Configuration management Verification/validation Quality assurance (reviews, audits, …) Subcontract Process improvement plan Annexes Index

Effective Project Control Detailed planning Deliverables and measurable milestones Communication Tracking (money, time, resources, tasks) Reviews Signing-on Reasons for poor control?

Project Tracking Activities tracking Defect tracking Issues tracking Use Microsoft Project or similar tools Percent completed Defect tracking Submission, injection, detection, closure dates Type, severity, people involved Related changes Issues tracking Small jobs, … Status reports

Milestone Analysis Actual vs. estimated effort and schedule Re-schedule Scheduling training Review tasks Quality monitoring Review test procedure More tests Risk-related monitoring