# Software equation

Software equation

In the study of software project estimation, the Software Equation is a model with multiple variables based on assumptions of a specific distribution of effort throughout the entire length of a software development project. The models basis was formed through analysis of productivity data collected from over 4000 modern day software development projects.cite book|last=Pressman|first=Roger S.|authorlink=Roger S. Pressman|title=Software Engineering - A Practitioner's Approach|origdate=1982|edition=6th|publisher=McGraw-Hill|location=Newyork, NY|year=2005|isbn=0-07-285318-2|pages=662-663] The software equation was derived from the Putnam-Norden-Rayleigh Curve which can be used to show the non-linear correlation between time to complete the project and applied human effort.cite book|last=Pressman|first=Roger S.|authorlink=Roger S. Pressman|title=Software Engineering - A Practitioner's Approach|origdate=1982|edition=6th|publisher=McGraw-Hill|location=Newyork, NY|year=2005|isbn=0-07-285318-2|pages=679]

Model Form

The estimation model can be described in the following form.

:$E=left lbrack frac\left\{LOC x B^\left\{.333\left\{P\right\} ight brack^3 left \left( frac\left\{1\right\}\left\{t^4\right\} ight \right)$

where

*E=Project effort measured in person-months or person-years
*LOC=a Lines of Code estimate for the project
*t=Length of project measured in months or years
*B=a "special skills factor"
*P=a "Productivity Parameter"

Defining B

B, the special skills factor, is related to the size of the product.Citeweb|url=http://www.sju.edu/~jhodgson/se/compeq.html|title=The Computational Software Equation|accessdate=2007-09-06]

Defining P

Research from the collected productivity data supplies initial values for variable P determined by the type of software being developed. Some examples are listed below. These numbers to not apply in all situations and P can often be calculated from previous metrics information.

ee also

*Putnam-Norden-Rayleigh Curve

References

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Software Security Assurance — Software is itself a resource and thus must be afforded appropriate security. Software also contains and controls data and other resources. Therefore, it must be designed and implemented to protect those resources. Software Security Assurance is… …   Wikipedia

• Software brittleness — The term software brittleness refers to the increased difficulty in fixing older software that may appear reliable, but fails badly when presented with unusual data or altered in a seemingly minor way. The term is derived from analogies to… …   Wikipedia

• Software Arts — Infobox Company company company name = Software Arts company type = Private company slogan = foundation = 1979 location = Cambridge, Massachusetts, Newton, Massachusetts key people = Co founders Dan Bricklin, Bob Frankston num employees =… …   Wikipedia

• Structural equation modeling — (SEM) is a statistical technique for testing and estimating causal relations using a combination of statistical data and qualitative causal assumptions. This definition of SEM was articulated by the geneticist Sewall Wright (1921),[1] the… …   Wikipedia

• Ordinary differential equation — In mathematics, an ordinary differential equation (or ODE) is a relation that contains functions of only one independent variable, and one or more of their derivatives with respect to that variable. A simple example is Newton s second law of… …   Wikipedia

• Groundwater flow equation — Used in hydrogeology, the groundwater flow equation is the mathematical relationship which is used to describe the flow of groundwater through an aquifer. The transient flow of groundwater is described by a form of the diffusion equation, similar …   Wikipedia

• Maple (software) — Maple Maple interface Developer(s) Waterloo Maple (Maplesoft) Stable release 15.01 / June 21, 2011; 4 months ago (2011 06 21) …   Wikipedia

• Differential algebraic equation — In mathematics, differential algebraic equations (DAEs) are a general form of (systems of) differential equations for vector–valued functions x in one independent variable t, where is a vector of dependent variables and the system has as many… …   Wikipedia

• Microsoft Equation Editor — Infobox Software name = Microsoft Office Equation Editor caption = Equation Editor under Microsoft Office 2007. The linear input a=(b/c)^x+... would produce this output. developer = Microsoft latest release version = 2007 operating system =… …   Wikipedia

• Parametric equation — butterfly curve. In mathematics, parametric equations are a method of defining a curve. A simple kinematical example is when one uses a time parameter to determine the position, velocity, and other information about a body in motion.Abstractly, a …   Wikipedia