Winter 2002 Software Cost Estimation by Samuel Lee ) Lance Titchkosky ) Seth Bowen ) Department of Computer Science University of Calgary Contents 1. Abstract Software projects are notorius for going past their deadline, going over budget, or both. The problem lies in the estimation of the amount of effort required for the development of a project. The cost estimation is usually dependent upon the size estimate of the project, which may use lines of code or function points as metrics (see ). There are several different techniques for performing software cost estimation, including expert judgement and algorithmic models. Estimation by expert judgement is a common way of estimating the effort required for a project. Unfortunately, this method of estimation does not emphasize re-estimation during the project life cycle, which is an important part of project tracking, because it allows the estimates to be improved during the project life cycle. Spiral model is an evolutionary software process model. And the advantages and disadvantages of spiral model. Models in software engineering. The quality of a cost estimation model is not so much attributed to the initial estimate, but rather the speed at which the estimates converges to the actual cost of the project. COCOMO is a popular algorithmic model for cost estimation whose cost factors can be tailored to the individual development environment, which is important for the accuracy of the cost estimates. ![]() More than one method of cost estimation should be done so that there is some comparison available for the estimates. This is especially important for unique projects. Cost estimation must be done more diligently throughout the project life cycle so that in the future there are fewer surprises and unforseen delays in the release of a product. Introduction Studies within the last few years have shown that a great deal more money is often spent on projects than is initially anticipated. IBM's Consulting Group did a survey of 24 leading companies in 1994 and found that 55% of the software developed cost more than the initial cost estimates (). The Standish Group also did a study in 1994 of 8,380 projects in the United States and found that 53% of the software projects that were completed cost 189% of the original estimates (). Although these numbers are from a few years ago, they likely have not changed much recently (). The problem of making accurate cost estimates can be attributed to a number of reasons: the wrong cost estimation processes may be used, no processes may be used, or the nature of the problem may not allow for accurate cost estimation. Cost estimation is an often overlooked project management practice. 2.1 Defining Cost Estimation Cost estimation can be defined as the approximate judgement of the costs for a project. Bujias ngk mexico. Cost estimation will never be an exact science because there are too many variables involved in the calculation for a cost estimate, such as human, technical, environmental, and political. Futhermore, any process that involves a significant human factor can never be exact because humans are far too complex to be entirely predictable. Furthermore, software development for any fair-sized project will inevitably include a number of tasks that have complexities that are difficult to judge because of the complexity of software systems. Conexant smart hcf p9573-11 driver. ![]() Cost estimation is usually measured in terms of effort. The most common metric used is person months or years (or man months or years). The effort is the amount of time for one person to work for a certain period of time. It is important that the specific characteristics of the development environment are taking into account when comparing the effort of two or more projects because no two development environments are the same. A clear example of differences in development environments are the amount of time people work in different countries; the typical workweek in North America is 40 hours per week, while in Europe the typical workweek is 35 hours per week (). Thus, when comparing a project from North America with a project from Europe, a conversion factor would have to be used to all for an accurate comparison. Different variables can be used for cost estimation, which leads to a difficulty when comparing projects if standard models or tools are not used. For example, a cost estimate can include factors from management, development (e.g., training, quality assurance), and other areas specific to an organization. 2.2 Cost Estimation and Project Planning Cost estimation is an important tool that can affect the planning and budgeting of a project. Because there are a finite number of resources for a project, all of the features of a requirements document can often not all be included in the final product. A cost estimate done at the beginning of a project will help determine which features can be included within the resource constraints of the project (e.g., time). Requirements can be prioritized to ensure that the most important features are included in the product.
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