Last updated 10/22/2001
Data Collection Program
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One source of pre-existing software is commercial vendors who supplyself-contained off-the-shelf components that can be plugged into a largersoftware system to provide capability that would otherwise have to be custombuilt. The two primary distinguishing characteristics of this so-calledCOTS (commercial-off-the-shelf) software are 1) that its source code isnot available to the application developer, and 2) that its evolution isnot under the control of the application developer.
The rationale for building COTS based systems is that they will involveless development time by taking advantage of existing, market proven, vendorsupported products, thereby reducing overall system development costs.But because of the two defining characteristics noted above (lack of accessto product source code, and lack of control over product evolution), thereis a trade-off in using the COTS approach in that new software developmenttime can indeed be reduced, but generally at the cost of an increasein software component integration work. Moreover, using COTS software alsobrings with it a host of unique risks quite different from those associatedwith software developed in-house.
Included among those risks or factors which should be examined whendetermining the true cost of integrating a COTS software componentinto a larger system are not only the traditional costs associated withnew software development such as the cost of requirements definition, design,code, test, and software maintenance, but also the cost of licensing andredistribution rights, royalties, effort needed to understand the COTSsoftware, pre-integration assessment and evaluation, post-integration certificationof compliance with mission critical or safety critical requirements, indemnificationagainst faults or damage caused by vendor supplied components, and costsincurred due to incompatibilities with other needed software and/or hardware.
Because of these unique risks, using COTS components in the developmentof new systems is not the universal solution to reducing cost andschedule while maintaining desired quality and functionality. However,ifthese risks can be managed, using COTS components can frequently bethe right solution, offering the most cost-effective, shortest scheduleapproach to assembling major software systems.
COTS components are the right solution when they lie at the intersectionof the three determinants of feasibility--technical, economic, and strategicconstraints--and do so in a way demonstrably better than if a new systemwere to be constructed entirely out of original software. The key tosuccess in using COTS components is being able to identify whether theyfit the current procurement situation--technically, economically, and strategically.Technically, they have to be able to supply the desired functionality atthe required level of reliability. Economically, they have to be able tobe incorporated and maintained in the new system within the availablebudget and schedule. Strategically, they have to meet the needs of thesystem operating environment--which includes technical, political, andlegal considerations--now, and as that environment is expected to evolvein the future.
|The determinants of COTS component feasibility: Technical,Economic, and Strategic constraints.|
Technical and strategic feasiblility is determined during the candidateassessment phase of procuring COTS products, which occurs at the startof a COTS integration activity. How to determine the viability of a COTSproduct in either of these two dimensions is not a trivial question, andcan be partially addressed by using the COCOTS Assessment submodel. However,it is the third dimension of determining economic feasibility whichis the main intended use of COCOTS.
To answer the question of economic feasibility, cost estimation modelsexist which capture the traditional costs associated with new softwaredevelopment noted above, among the most prominent being COCOMO®.To date, however, very few estimation models have been developed whichtry to capture those other costs unique to using COTS components in a softwaresystem development. The number of COTS integration cost models availablein the public domain currently approaches zero. In response to this situation,USC-CSE has been actively pursuing COTS integration cost modeling researchsince 1995. The most recent result of this research is COCOTS (COnstructiveCOTS), a cost estimation model designedto capture explicitly the most important costs associated with COTS componentintegration.
For your convenience, we are providing for download copies of the COCOTSresearch overview statement, the COCOTS data collection instrument, andthe standard confidentiality agreement USC-CSE enters into with most ofour data suppliers. We have proven procedures that we have followed successfullyfor over four years in the development of COCOMO®II to prevent the compromise of any information entrusted to us thatcould be considered proprietary by data suppliers. We are using these sameprocedures in the collection of data for COCOTS. We would also be gladto discuss any specific accommodations you might need to permit your participationin this data collection effort. For further information or to discuss participationin the COCOTS data collection program, please contactus.
Data Collection Documents:
In addition to the on-going support provided by the USC-CSEAffiliates, the COCOTS research effort has been funded by the USAFElectronic Systems Center/Rome Laboratory,the Federal Aviation Administration, andthe Office of Naval Research. Wewould like to thank these organizations for their assistance while acknowledgingthat their support does not constitute an endorsement by any of these organizationsof the COCOTS model over any other similar cost estimation tool.
|Link to the COCOMO®Page |
COCOMO® II is the new cost model replacing COCOMO® 81. It is the parentmodel to COCOTS, capturing software development costs outside the scopeof COCOTS relating to the development of new and reuse software components.
For information on the entire suite of COCOMO®-related cost models go here.
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