CO-IMP-MO – the use of COCOMO II to improve Rolls-Royce

1. CO-IMP-MO – the use of COCOMO II to improve Rolls-Royce Andy Nolan BSc Hons, CEng, FBCS, CITP Chief of Software improvement – The Software Centre of Excellence Satpaul Sall BSc Hons Software Technologist – The Software Centre of Excellence

2. Abstract • Validating Improvement Initiatives - Using COCOMO to verify improvement projects/programmes being delivered by the engineering organisation. Are we failing to recognise which areas of improvement we need to be tackling as a business? COCOMO has allowed us to show Rolls-Royce the key factors affecting programme/project performance & effectiveness. This has had big pull from the corporate Engineering Improvements team who want to use this method to verify many improvement projects. The presentation provides an overview of the tool and some of the results it produces.

4. The need for Software Product Lines 4 • The Control Systems department is responsible for the Engine Electronic Controllers (EECs) for a range of small and large gas turbine engines for the aerospace industry. • The software is developed to DO-178B Level-A standards • The company has been developing high integrity software for over 20 years and has extensive data on its processes and productivity. • We have the largest order book in history, new engine development places greater demand on the software team (shorter time scales and lower costs)

5. The Philosophy An improvement project should be estimated and managed to the same rigour as a development project of its equivalent size and risk

6. CO-Bus-MO Enterprise business performance Software Supplier COCOMO Challenging our supplier costs. Benchmarking the business Hardware COCOMO CO-RISK-MO Risk Management Using the model to identify and quantify risk Using many SW factors to estimate hardware engineering CO-Imp-MO Improvement COCOMO Hardware Supplier COCOMO Using COCOMO to identify & validate improvements Estimation & eliciting key assumptions & negotiation COCOMO A unifying language

7. Estimation Elicitation Diagnostics CO-Bus-MO Enterprise business performance Software Supplier COCOMO Estimation & eliciting key assumptions & negotiation Challenging our supplier costs. Benchmarking the business COCOMO A unifying language Hardware COCOMO CO-RISK-MO Risk Management Using the model to identify and quantify risk Using many SW factors to estimate hardware engineering CO-Imp-MO Improvement COCOMO Hardware Supplier COCOMO Using COCOMO to identify & validate improvements

8. The problem Improvements are often peoples “pet” subjects, based on politics, overlook the “elephant in the room”, lack evidence to justify their claims and can easily overspend and under-succeed

9. COCOMO is at the heart of our business Business Goals • Anticipate risk • Identify improvements • Validate improvements • Benchmark the business • Make better decisions Set Project Goals & Targets Estimate & Plan Project Understand Capability Improve capability Monitor & Control Project Benchmark Capability

10. Estimating the Benefit of Improvements

11. The Philosophy If COCOMO II models the cost of a project then it can also model the benefits of improvements. Any improvement that does not affect a factor in COMO is unlikely to deliver significant engineering improvements

12. Estimating Improvement benefits Improvement COCOMO Benefit is calculated as the % influence over each COCOMO factor. Each COCOMO factor has a difference sensitivity and each improvement will affect each factor differently

13. Estimating Improvement benefits Improvement COCOMO Benefit is calculated as the % influence over each COCOMO factor. Each COCOMO factor has a difference sensitivity and each improvement will affect each factor differently %Benefit = %influence * COCOMO Factor Benefit

14. Estimating Improvement benefits Improvement Improvement Improvement COCOMO COCOMO COCOMO FTE’s affected is based upon the number of FTE’s in each business section multiplied by the % affected by the improvement initiative Sector FTE

15. Estimating Improvement benefits Improvement Improvement Improvement COCOMO COCOMO COCOMO Example 1 £/$Benefit = %Benefit * FTE * Hours per year * Cost Rate Sector FTE

16. Estimating Improvement benefits Improvement Improvement Improvement COCOMO Benefit is also affected by WHEN the improvements are expected to arise (time) COCOMO COCOMO Example 2 Sector FTE 10% 100% 50% 25% Year 50% 100% 50% 100% 75%

17. Estimating Improvement benefits Improvement Improvement Improvement Example 3 COCOMO COCOMO COCOMO Sector FTE 10% 100% 50% 25% Year 50% 100% 50% 100% 75% 10 100 50% 25 Cost£ 50 100 50 100 75

18. Estimating Improvement benefits Improvement Improvement Improvement COCOMO COCOMO COCOMO Sector FTE 10% 100% 50% 25% Year 50% 100% 50% 100% 75% 10 100 50% 25 Cost£ 50 100 50 100 75

19. Eliciting Improvement

20. Project 3-point Estimate Improvement Log Risk Log

21. Business Average Performance Best Value Nominal Value Business average: where the business needs to invest Worst Value

22. Diagnostics Tool Best Value Nominal Value Worst Value Business average: where the business needs to invest

23. Conclusion

24. Conclusions • COCOMO II challenges the business • Are our improvements worthwhile • Are we improving the right things • It has had the effect of • Stopping some initiatives • Changing many other initiatives • Creating new ideas in the business

25. An Observation Often, just the existence of COCOMO II and its factors is enough to change project and business behaviour for the better.