ISSN : 1796-217X
Volume : 4    Issue : 5    Date : July 2009

An Improved Fuzzy Approach for COCOMO’s Effort Estimation Using Gaussian Membership Function
Ch. Satyananda Reddy and KVSVN Raju
Page(s): 452-459
Full Text:
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In software industry Constructive Cost Model (COCOMO) is considered to be the most widely used
model for effort estimation. Cost drivers have significant influence on the COCOMO and this research
investigates the role of cost drivers in improving the precision of effort estimation. It is important to
stress that uncertainty at the input level of the COCOMO yields uncertainty at the output, which leads to
gross estimation error in the effort estimation. Fuzzy logic has been applied to the COCOMO using the
symmetrical triangles and trapezoidal membership functions to represent the cost drivers. Using
Trapezoidal Membership Function (TMF), a few attributes are assigned the maximum degree of
compatibility when they should be assigned lower degrees. To overcome the above limitation, in this
paper, it is proposed to use Gaussian Membership Function (GMF) for the cost drivers by studying the
behavior of COCOMO cost drivers. The present work is based on COCOMO dataset and the
experimental part of the study illustrates the approach and compares it with the standard version of the
COCOMO. It has been found that Gaussian function is performing better than the trapezoidal function,
as it demonstrates a smoother transition in its intervals, and the achieved results were closer to the
actual effort.

Index Terms
COCOMO, Fuzzy based effort estimation, Gaussian membership function, Software cost estimation,
Software effort estimation and Project management