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Summary

Software cost estimation is the process of predicting the effort required to develop a software system. This paper provides an overview of methods for estimating software costs, including recent advances in the field. Like a number of these models are based on an estimate of the size of software as input, we first give an overview of regular size. We then present models for estimating costs that have been proposed and used successfully. Models can be classified into two broad categories: algorithmic and non-algorithmic. Each has its own strengths and weaknesses. A key factor in selecting a model to estimate costs is the accuracy of its estimates. Unfortunately, despite extensive experience with assessment models, the accuracy of these models are not satisfactory. The document includes comments on the performance estimation models and descriptions of several new

approaches for estimating costs.

project effort estimation, estimation of cost models: Keywords.

 

1. Introduction

 

In recent years, software has become the most expensive component of information systems projects. Much of the cost of developing software is due to human effort, and most methods for estimating costs to focus on this aspect and give estimates in terms of person-months.

Accurate estimates of software costs are essential for developers and customers. They can be used to generate the request for proposals, contract negotiation, planning, monitoring and control. Underestimating costs may result in the management of the approval of the proposed system then exceed their budgets, with features of underdeveloped and of poor quality and lack of finishing on time. The overestimation can lead to too many resources committed to the project or, in contract bidding can not win the contract, which may lead to job losses

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accurate estimate of costs is important because:

• It can help to categorize and prioritize development projects compared to a comprehensive business plan.
• It can be used to identify resources to undertake the project and how these resources will be used.
• It can be used to assess the impact of changes and re-planning support.
• Projects may be easier to manage and control when resources are better suited to actual needs.
• Customers expect actual development costs to be in line with estimated costs.
• Software cost estimation involves the determination of one or more of the following estimates:

• effort (usually in person-months)
• project duration (in calendar time)
• cost (in dollars)

 

Most cost estimation models attempt to generate an estimate of the effort, which can then be

converted into the project duration and costs. Despite the effort and costs are closely related, they are not necessarily bound by a simple transformation function. Effort is often measured in person-months of programmers, analysts and project managers. This effort estimation can be converted into a dollar cost figure by calculating an average wage per unit of staff time involved, then multiplying by the estimated effort required.

Practitioners have struggled with three basic questions:

• What model of cost estimation software to use?
• Which measure of the size of software to use - lines of code (LOC), function points (FP), or point function?
• What is a good estimate?

The widely practiced method of cost estimation is an expert judgment. For many years, the project

managers have relied on the experience and industry standards in force as the basis for developing cost estimates. However, estimat basis.