EstimationEstimation is the process of finding an estimate, or approximation, which is a value that can be used for some purpose even if input data may be incomplete uncertain or unstable.

Project Estimation And Software Engineering• Software engineers have very poor track record of estimating project

effort because software as product is very complex to measure and estimate.• We have just 50 YEARS of history to look back at softwares and get

some glimpse of shining north star of guidance.

Why We(software engineers) NEED to estimate??

• Bosses needs estimates before allotting resources.• Software Firm has to put a bid for a project.• Is it going to be in-house project or to

outsource?!• Freelancing is all about estimating.

Project Estimation Approaches• Analogous cost estimation• Parametric Estimation• Three-point Estimation• Bottom-up Estimation

Wide Band Delphi• Delphi Method is a structured

communication technique, originally developed as a systematic, interactive forecasting method which relies on a panel of experts. The experts answer questionnaires in two or more rounds. After each round, a facilitator provides an anonymous summary of the experts’ forecasts from the previous round with the reasons for their judgments. Experts are then encouraged to revise their earlier answers in light of the replies of other members of the panel.

• The term "wideband" is used because, compared to the Delphi Method the Wideband Delphi Technique involved greater interaction and more communication between the participants. In Wideband Delphi Technique, the estimation team comprise the project manager, moderator, experts, and representatives from the development team, constituting a 3-7 member team.

Work Breakdown Structure• WBS is a deliverable-oriented

decomposition of a project into smaller components. • WBS is represented as a

hierarchical list of project’s work activities

• Precedence: A task that must occur before another is said to have precedence ofthe other. • Concurrence: Concurrent tasks are

those that can occur at the same time .• Critical Path: Specific set of sequential

tasks upon which the project completion date depends.

PERT and CPM

•PERT is based on three values: most optimistic estimate (O), a most likely estimate (M),and a pessimistic estimate (least likely estimate (L)).

E = (O+4 × M+L)/6

• Critical Path Method (CPM) is technique to arrange critical project task in order and hierarchy.

Planning Poker• Planning Poker is a estimation

technique , mostly used to estimate effort or relative size of user stories in Scrum.

• Planning poker combines three methods of estimation - Expert Opinion Analogy Disaggregation

Estimation Guidelines• During estimation, ask other people's experiences. Also, put your own experiences

at task. • Include management time in any estimate. • Where possible, use documented data from your organization’s similar past projects. • Always prefer developer-based estimates.• Use several different people to estimate and use several different estimation

techniques.