What are the main functions performed by the automated estimation tools? Describe each function briefly.
Automated Estimation Tools:-
Automated estimation tools allow the planner to estimate cost and effort and to perform "what if" analyses for important project variables such as delivery date or staffing.
All have the same general characteristics and require:
1. A quantitative estimate of project size (e.g., LOC) or functionality
2. Qualitative project characteristics such as complexity, required reliability, or business criticality
3. Some description of the development staff and/or development environment
From these data, the model impleme
nted by the automated estimation tool provides estimates of the effort required to complete the project, costs, staff loading, and, in some cases, development schedule and associated risk.
COCOMO 2.0 is the successor to COCOMO, which is described in Barry Boehm's 1981 book Software Engineering Economics
BYL (Before you leap) developed by the Gordon Group,
WICOMO (Wang Institute Cost Model) developed at the Wang Institute
are automated estimation tools that are based on COCOMO.
Each of the tools requires the user to provide preliminary LOC estimates.
These estimates are categorized by programming language and type.
The user also specifies values for the cost driver attributes.
Each of the tools produces estimated elapsed project duration (in months), effort in staff-months, average staffing per month, average productivity in LOC/pm, and cost per month. This data can be developed for each phase in the software engineering process individually or for the entire project.
SLIM is an automated costing system based on the Rayleigh-Putnam Model.
SLIM applies the Putnam software model, linear programming, statistical simulation, and program evaluation and review technique, or PERT (a scheduling method) techniques to derive software project estimates.
The system enables a software planner to perform the following functions in an interactive session:
(2) create an information model of the software to be developed by eliciting basic software characteristics, personal attributes, and environmental considerations; and
(3) conduct software sizing--the approach used in SLIM is a more sophisticated, automated version of the LOC costing technique.
Once software size (i.e., LOC for each software function) has been established, SLIM computes size deviation (an indication of estimation uncertainty), a sensitivity profile that indicates potential deviation of cost and effort, and a consistency check with data collected for software systems of similar size.
The planner can invoke a linear programming analysis that considers development constraints on both cost and effort, and provides a month-by-month distribution of effort, and a consistency check with data collected for software systems of similar size.
ESTIMACS is a "macro- estimation model" that uses a function point estimation method enhanced to accommodate a variety of project and personnel factors.
The ESTIMACS tool contains a set of models that enable the planner to estimate
1. system development effort,
2. hardware configuration,
It can develop staffing and costs using a life cycle data base to provide work distribution and deployment information.
The target hardware configuration is sized (i.e., processor power and storage capacity are estimated) using answers to a series of questions that help the planner evaluate transaction volume, windows of application, and other data.
The level of risk associated with the successful implementation of the proposed system is determined based on responses to a questionnaire that examines project factors such as size, structure, and technology.
\developed by Software Productivity Research, Inc. has the user complete a simple set of multiple choice questions that address:
project type (e.g., new program, maintenance), project scope (e.g., prototype, reusable module), goals (e.g., minimum duration, highest quality), project class (e.g., personal program, product), application type (e.g., batch, expert system), novelty (e.g., repeat of a previous application), office facilities (e.g., open office environment, crowded bullpen), program requirements (e.g., clear, hazy), design requirements (e.g., informal design with no automation), user documentation
In addition to output data described for other tools, SPQR/20 estimates:
• total pages of project documentation,
• total defects potential for the project,
• cumulative defect removal efficiency,
• total defects at delivery, and
Each of the automated estimating tools conducts a dialog with the planner, obtaining appropriate project and supporting information and producing both tabular and (in some cases) graphical output.
All these tools have been implemented on personal computers or engineering workstations.