THE FOUR BASIC CONSTITUENTS OF A SEMI- PARAMETRIC ENGINEERING EFFORT ESTIMATION
Hartmut Steck-Winter · 2008
In order to precisely estimate the effort related t o the engineering design process, there is a need for empirically tested methods which expl oit the results already achieved in related engineering fields. Similar to software cost estimation methods, the pr oposed engineering design effort equitation contains four basic constituents with th ree different types of parameters: additive, multiplicative, and exponential. Nominal size effort is calculated additive utilisin g the bottom-up approach. Although the effort estimation procedure is aimed to be semi -parametric, for good reasons, nominal size estimation remains to be an expert estimation. Effort divers respectively the complexity driver ar e exponential because they have both a global effect and an emergent effect for lar ger projects. Effort drivers are used to adjust nominal size to the complexity level of the require ments. Stochastic influence factors are multiplicative bec ause they all have global effects across the overall system. Influence factors are us ed to adjust engineering effort estimation to the dynamics of the environment. Larger engineering tasks will require proportionall y more engineering effort than smaller engineering tasks. Therefore, the fourth an d final part of the equitation is an exponential size driver. The identification of effort drivers and stochastic influence factors is pivotal to engineering design effort estimation. Effort driver s and influence factors were defined after extensively surveying recent engineering literature 1 followed by an explorative research of five engineering design projects.