Function points and software metrics 1 function points and software metrics presentation provided complimentary by david longstreet. Introduction to function point analysis software metrics. The use of function points and related metrics is commonly incorporated into a division or organizationwide measurement and processimprovement program. Experienced software professionals fully understand the merits of function points over agile story points as the primary size metric for a software project.
Function point training our function point training course has emerged from our global consulting practice. In this article, dan demonstrates the use of fpa in agile development through a handson example. Software size estimation theory of function pointfp. Estimating software and measuring projects function point. Most software language have published averages for lines of code per function point. The method used to calculate function point is knows as fpa function point analysis. Now customize the name of a clipboard to store your clips.
Basically, the analysis based on function points can be compared to slicing the problem into smaller parts. Software metrics are measures of the success of a software process. So function oriented software metrics rely on calculating the function point fp a unit of measurement that quantifies the business functionality provided by the product. It measures functionality from the users point of view i. Improve your agencys performance by measuring metrics. Notes on the slides have been included to assist you in your understanding. The method was first published in 1979, then later in 1983. The function point fp methodology is one of the most known techniques used to measure software. We have worked with companies in nearly every business line, a variety of sizes and companies around the globe. Software requirements metrics fairly primitive and predictive power limited.
Measuring with function points function point measures. Feature point is the superset of function point measure that can be applied to systems and engineering software applications. Function point counting delivers reliable metrics for improving application analysis. Function points as a universal software metric acm. Counting the lines of code and dividing by this number is called backfiring. In the future function point metrics can easily become a universal metric used for all software applications and for all software contracts in all countries. There is international function point users group in us based organization of users of the software metric function point analysis every function point is a unit of measure used by ifpug functional size measurement method. In short, agile story points tend to vary in size up to 400% from team to team and are principally an indication of effort rather than functional size based on user requirements. Count the number of functions of each proposed type. The function point is a unit of measurement to express the amount of business functionality an information system as a product provides to a user. Function point analysis was developed first by allan j. Solved numerical examples of function point calculation software engineering in hindi duration. This article describes common uses of the function point metric by the software development organization.
In theory, metrics can help to improve the development process and provide companies with information that makes future projects more predictable, efficient, etc. Function points count number of inputs and output, user interactions, external interfaces, files used. Function points are one of the most widely used measures of software size. Function points are also useful for comparing software projects written in different languages. The cost in dollars or hours of a single unit is calculated from past projects.
With fpa function points analysis systems are divided into smaller software components, what makes them easier to analyze and understand. Uses and benefits of function points total metrics. Function points can be used to establish an inventory of all transactions and files of a current project or application 105. Function points are used a metric in software testing. Function points are technologically independent, consistent, repeatable, and help normalize data, enable comparisons, and. With function point s agency management software, agencies can quickly and easily measure the metrics that matter most to them. The ifpug fsm is one of the currently recognized standards of iso for functionally sizing software. The next step in measuring metrics that matter without measuring metrics, agencies are behind the eightball in understanding the biggest influences impacting margin, utilization and expenses. Function point metrics are the most accurate and effective metrics yet developed for software sizing and also for studying software productivity, quality, costs, risks, and economic value. Function point analysis fpa, is used to measure the size functions of software. They are widely accepted as an industry standard for functional sizing. Function point metrics provide a standardized method for measuring the various functions of a software application.
Function point analysis fpa is a method or set of rules of functional size measurement. Used to predict size or cost and to assess project productivity. Measurement practices for successful software projects is a comprehensive presentation of the principles of function point analysis fpa and a guide to its effective use in managing the development and deployment of software. The basis of function points is that the functionality of the system that is. Clipping is a handy way to collect important slides you want to go back to later. Function point metrics, measure functionality from the users point of view, that is, on the basis of what the user requests and receives in return. Software engineering project size estimation techniques. Function points per person per month rates used in industry. Assess each for complexity and multiply by a weighting factor. To demonstrate the versatility of the function point metric, we have selected two scenarios. Ibms development of function point metrics the author was working at ibm in the 1960s and 1970s and was able to observe the origins of several ibm technologies such as inspections, parametric estimation tools, and function point metrics.
Please make any necessary modifications to meet your specific needs. It was an attempt to overcome difficulties associated with lines of code as a measure of software size, and to assist in developing a mechanism to predict effort associated with software development. Back to measuring application complexity, here is where function points play important role. It is the software which is relocated to the production application at project implementation. Function points are used to compute a functional size measurement fsm of software. Function point analysis helps developers and users quantify the size and complexity of software application functions in a way that is useful to software users. Function points can be used to size software applications.
These programs vary widely among companies and even within organizations. A function point fp is a component of software development which helps to approximate the cost of development early in the process. Measuring software for dummies function point methodology. A function point fp is a unit of measurement to express the amount of business functionality, an information system as a product provides to a user.
Albrecht initially developed function point analysis in 1979 at ibm and it has been further modified by the international function point users group ifpug. Why we should use function points software metrics. We cover the use of function points and other software metrics at both the. For sizing software based on fp, several recognized standards andor public specifications have come into existence. Function point provides the best workflow and agency management software that helps professional creative service agencies run their businesses more efficiently by combining project management, time tracking, budgeting, resourcing, reporting, and much more with one tool. All software projects are not required to construction of dfd. Software metrics massachusetts institute of technology.
Function points are used at the it management level as. Function points are consistent and independent of design. For example 50 lines of java is, on average, equivalent to one function point. Cyclomatic complexity, is used to measure code complexity. Traditionally, function point counting is done by trained, certified function point counters. They are used to measure the size of the software, functionality by measuring the requirements. In an earlier article, dan horvath explored some history and definitions of agile and how function point analysis fpa can be used in the measurement of agile projects. The outcome of a function point count provides the metric unit of software delivered and can be used to assist in the management and control of software development, customisation or major enhancements from early project planning phases, through to the ongoing support of the application. It is a process which defines the required functions and their complexity in a piece of software in order to estimate the software s size and scope upon completion.
Sizing is an important component in determining productivity outputsinputs, predicting effort, understanding unit cost, so on and so forth. Estimation techniques function points tutorialspoint. Function point counting methodology is the least inaccurate measurement approach for determining software size. Fpa is used to make estimate of the software project, including its testing in terms of functionality or function size of the software product. Unlike the older lines of code metric function points can be used to study requirements, design, and in fact all software activities from development. Basically, as applied to the software product, a software metric measures or quantifies a characteristic of the software. Also i would define it in single line as a method of quantifying the size and complexity of a software system in terms of the functions that the system delivers to the user. Written for both information technology it practitioners and managers, it describes how to use this provenbutunderutilized software sizing. In this method, the number and type of functions supported by the software are utilized to find fpc function point count. Dan emphasizes that the definition of the project is critical to this process.
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