In project management (e.g., for engineering), accurate estimates are the basis of sound project planning. Many processes have been developed to aid engineers in making accurate estimates, such as
Project management is the practice of initiating, planning, executing, controlling, and closing the work of a team to achieve specific goals and meet specific success criteria at the specified time.
Engineering is the use of scientific principles to design and build machines, structures, and other things, including bridges, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. See glossary of engineering.
Project planning is part of project management, which relates to the use of schedules such as Gantt charts to plan and subsequently report progress within the project environment. Project planning can be done manually or by the use of project management software.
- Analogy based estimation
- Compartmentalization (i.e., breakdown of tasks)
- Cost estimate
- Delphi method
- Documenting estimation results
- Educated assumptions
- Estimating each task
- Examining historical data
- Identifying dependencies
- Parametric estimating
- Risk assessment
- Structured planning
When referring to engineering, compartmentalization is the general technique of separating two or more parts of a system to prevent malfunctions from spreading between or among them. This entails the breaking up of a project or problem into sub classes and sub categories, with the intention of simplifying the task at hand, or to efficiently distribute it amongst a number of teams or people.
In project management, a task is an activity that needs to be accomplished within a defined period of time or by a deadline to work towards work-related goals. It is a small essential piece of a job that serves as a means to differentiate various components of a project. A task can be broken down into assignments which should also have a defined start and end date or a deadline for completion. One or more assignments on a task puts the task under execution. Completion of all assignments on a specific task normally renders the task completed. Tasks can be linked together to create dependencies.
A cost estimate is the approximation of the cost of a program, project, or operation. The cost estimate is the product of the cost estimating process. The cost estimate has a single total value and may have identifiable component values. A problem with a cost overrun can be avoided with a credible, reliable, and accurate cost estimate. A cost estimator is the professional who prepares cost estimates. There are different types of cost estimators, whose title may be preceded by a modifier, such as building estimator, or electrical estimator, or chief estimator. Other professionals such as quantity surveyors and cost engineers may also prepare cost estimates or contribute to cost estimates. In the US, according to the Bureau of Labor Statistics, there were 185,400 cost estimators in 2010. There are around 75,000 professional quantity surveyors working in the UK.
Popular estimation processes for software projects include:
- Cocomo
- Cosysmo
- Event chain methodology
- Function points
- Planning poker
- Program Evaluation and Review Technique (PERT)
- Proxy-based estimating (PROBE) (from the Personal Software Process)
- The Planning Game (from Extreme Programming)
- Weighted Micro Function Points (WMFP)
- Wideband Delphi
Event chain methodology is a network analysis technique that is focused on identifying and managing events and relationship between them that affect project schedules. It is an uncertainty modeling schedule technique. Event chain methodology is an extension of quantitative project risk analysis with Monte Carlo simulations. It is the next advance beyond critical path method and critical chain project management. Event chain methodology helps to mitigate the effect of motivational and cognitive biases in estimating and scheduling. It improves accuracy of risk assessment and helps to generate more realistic risk adjusted project schedules.
Planning poker, also called Scrum poker, is a consensus-based, gamified technique for estimating, mostly used to estimate effort or relative size of development goals in software development. In planning poker, members of the group make estimates by playing numbered cards face-down to the table, instead of speaking them aloud. The cards are revealed, and the estimates are then discussed. By hiding the figures in this way, the group can avoid the cognitive bias of anchoring, where the first number spoken aloud sets a precedent for subsequent estimates.
Proxy-Based Estimating (PROBE) is an estimating process used in the Personal Software Process (PSP) to estimate size and effort.
