4.    Schedule Estimation

The initial version of COCOMO II provides a simple schedule estimation capability similar to those in COCOMO 81 and Ada COCOMO.  The initial baseline schedule equation for the COCOMO II Early Design and Post-Architecture stages is:

                                                                           Eq. 14

In Equation 14, C is a TDEV coefficient that can be calibrated, PMNS is the estimated PM excluding the SCED effort multiplier as defined in Equation 1, D is a TDEV scaling base-exponent that can also be calibrated. E is the effort scaling exponent derived as the sum of project scale drivers and B as the calibrated scale driver base-exponent (discussed in Sections 3.1). SCED% is the compression / expansion percentage in the SCED effort multiplier rating scale discussed in Section 3.2.1.

Time to Develop, TDEV, is the calendar time in months between the estimation end points of LCO and IOC for MBASE/RUP or SRR and SAR for Waterfall lifecycle models (see Section 6.2).  For the waterfall model, this goes from the determination of a product’s requirements baseline to the completion of an acceptance activity certifying that the product satisfies its requirements.  For the MBASE/RUP model discussed in [Boehm et al. 2000], it covers the time span between LCO and IOC milestones.

As COCOMO II evolves, it will have a more extensive schedule estimation model, reflecting the different classes of process models a project can use.  The effects of reusable and COTS software; the effects of applications composition capabilities; and the effects of alternative strategies such as Rapid Application Development are discussed in [Boehm et al. 2000; also at http://sunset.usc.edu/COOCMOII/suite.html].