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
©2011 Rolls-Royce plc
The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose
other than that for which it is supplied without the express written consent of Rolls-Royce plc.
This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given
concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of
its subsidiary or associated companies.
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.
Rolls-Royce data
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Rolls-Royce data
The need for Software Product Lines
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 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 DO178B 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)
Rolls-Royce data
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
Rolls-Royce data
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Benchmarking
the business
CO-Bus-MO
Enterprise
business
performance
CO-RISK-MO
Risk
Management
Using the model
to identify and
quantify
risk
Rolls-Royce data
CO-Imp-MO
Improvement
COCOMO
Estimation &
eliciting key
assumptions &
negotiation
Software
Supplier
COCOMO
COCOMO
Hardware
COCOMO
A unifying
language
Using COCOMO
to identify &
validate
improvements
Challenging
our supplier
costs.
Hardware
Supplier
COCOMO
Using many SW
factors to
estimate
hardware
engineering
Benchmarking
the business
CO-Bus-MO
Enterprise
business
performance
CO-RISK-MO
Risk
Estimation
Management
Using the model
to identify and
quantify
risk
Rolls-Royce data
Elicitation
CO-Imp-MO
Improvement
COCOMO
Estimation &
eliciting key
assumptions &
negotiation
Software
Supplier
COCOMO
COCOMO
Hardware
COCOMO
A unifying
language
Using COCOMO
to identify &
validate
Diagnostics
improvements
Challenging
our supplier
costs.
Hardware
Supplier
COCOMO
Using many SW
factors to
estimate
hardware
engineering
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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 undersucceed
Rolls-Royce data
COCOMO is at the heart of our business
Business Goals
Set Project
Goals & Targets
Anticipate risk
 Identify improvements
 Validate improvements
 Benchmark the business
 Make better decisions

Estimate
& Plan Project
Understand
Improve
Monitor
Capability
capability
& Control Project
Benchmark
Capability
Rolls-Royce data
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Estimating the Benefit
of Improvements
©2011 Rolls-Royce plc
The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose
other than that for which it is supplied without the express written consent of Rolls-Royce plc.
This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given
concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of
its subsidiary or associated companies.
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
Rolls-Royce data
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COCOMO
Improvement
Rolls-Royce data
Estimating Improvement
benefits
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
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COCOMO
Improvement
Benefit
Estimating Improvement
benefits
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
Rolls-Royce data
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Sector FTE
COCOMO
COCOMO
Improvement
Improvement
Rolls-Royce data
Estimating Improvement
benefits
FTE’s affected is based upon the number
of FTE’s in each business section
multiplied by the % affected by the
improvement initiative
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Sector FTE
COCOMO
COCOMO
Improvement
Improvement
Rolls-Royce data
Estimating Improvement
benefits
Example 1
£/$Benefit = %Benefit *
FTE * Hours per year *
Cost Rate
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Improvement
Improvement
COCOMO
COCOMO
Estimating Improvement
benefits
Benefit is also affected by WHEN the
improvements are expected to arise (time)
Sector FTE
Example 2
Year
10%
50%
100%
Rolls-Royce data
100%
50%
25%
100%
50%
75%
Estimating Improvement
benefits
COCOMO
COCOMO
Improvement
Improvement
Sector FTE
Example 3
Year
10%
100%
50%
50%
25%
100%
50%
Cost£
100%
10
50
100
Rolls-Royce data
75%
100
50%
25
100
50
75
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Improvement
Improvement
Sector FTE
COCOMO
COCOMO
Estimating Improvement
benefits
Year
10%
100%
50%
50%
25%
100%
50%
Cost£
100%
10
50
100
Rolls-Royce data
75%
100
50%
25
100
50
75
Eliciting Improvement
©2011 Rolls-Royce plc
The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose
other than that for which it is supplied without the express written consent of Rolls-Royce plc.
This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given
concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of
its subsidiary or associated companies.
% Impact on Project Cost
-5%
New KSLOC
0%
-15%
Rolls-Royce data
-20%
Risk Log
FRAG - Task Fragmentation
TASK - Task Priority
MTOL - Management Tools
MEXP - Management Expereince
MCAP - Management Capability
Risks & Opportunities
SCED - development schedule
SITE - development sites
TOOL - tool capability
LTEX - language & tool experience
PLEX - platform experience
APEX - application experience
PCON - Personnel continuity
PCAP - programmer capability (code)
ACAP - Analyst capability
PVOL - platform volatility
STOR - storage use
TIME - execution time
DOCU - additional documentation
RUSE - developing for reuse
CPLX - complexity of product
DATA - test data complexity
RELY reliability
PMAT - Process maturity
TEAM - team cohesion
ARCH - Architectural resolution
RESL - Risk resolution
FLEX - Development flexibility
PREC - project precedentedness
S&R - % rework (planned or unplanned)
REVL (Req Evolution & Volatility)
-10%
Hours per Month
Project 3-point Estimate
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Improvement Log
Risk
Opportunity
15%
10%
5%
Business Average Performance
Best Value
Nominal Value
Business average: where the business needs to invest
Worst Value
Rolls-Royce data
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Diagnostics Tool
Best Value
Nominal Value
Worst Value
Business average: where the business needs to invest
Rolls-Royce data
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Conclusion
©2011 Rolls-Royce plc
The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose
other than that for which it is supplied without the express written consent of Rolls-Royce plc.
This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given
concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of
its subsidiary or associated companies.
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
Rolls-Royce data
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An Observation
Often, just the existence of
COCOMO II and its factors is
enough to change project and
business behaviour for the
better.
Rolls-Royce data