Integration of
Software Cost
Estimates
Across COCOMO, SEERSEM, and PRICE-S models
Tom Harwick, Engineering Specialist
Northrop Grumman Corporation
Integrated Systems
October 26-29, 2004
19th International Forum on COCOMO and Software Cost Modeling
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19th International Forum on COCOMO and Software Cost Modeling
Outline
• Need for Inter-Model Estimate Integration
• Model Analysis
– Model Comparisons & Sensitivity Analysis
– Economic Properties
• Baseline Example
– COCOMO
– SEER-SEM
– PRICE-S
• Summary
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19th International Forum on COCOMO and Software Cost Modeling
Need for Inter-Model Estimate Integration
• Communication of overall Software Cost Estimate to
the Customer
• Minimize Program Cost Risk
• Integration of Software Estimates Across Vendors
– Various Software Cost Models
– Sizing Definitions
– Selection of Cost Driver Settings
– Vendors have different Statement Of Work (SOW)
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis
• Approach
– Understand Properties of Each Cost Model
– Sizing and Sizing Normalization
– Productivity Cost Drivers
–Team & Process
–Market – Customer(s)
–Complexity, Operating Environment
–Model Scope Differences
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis
- Cost Drivers by Cost Model
Team & Process
Team
COCOMO II
ACAP, PCAP, APEX,
PLEX, LTEX
Process
TOOL, PCON, PVOL
Market/ Customer
Market
COCOMO II
RUSE, SITE, SECU *
Schedule
SCED
Reliability
Certification
Requirements
Complexity
Complexity
RELY
DOCU
Operating
Environment
&
Technology
Sizing & Exponent
Size
Normalized size
Exponent
Scope
Hardware dev. in
parallel with
software
System Integration
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COCOMO II
CPLX, DATA, STOR
TIME
COCOMO II
Raw KSLOC
Equiv. new KSLOC
PREC, FLEX, RESL,
TEAM,
PMAT- or SEI rating
COCOMO II
Not in the default model
SEER-SEM
Analyst Capabilities;
Analyst Experience;
Programmer
Capabilities;
Programmers Language
Experience
Development Method –
KnowledgeBase; and
Practices and Methods
Experience
SEER-SEM
Requirements
Definition Normality ;
Development Method –
Application and
Acquisition MethodKnowledgeBase;
Multiple Site
Development
Required Schedule;
Start Date
Development Standard KnowledgeBase
SEER-SEM
Application –
KnowledgeBase
Platform; and
DevelopmentMethod KnowledgeBase
SEER-SEM
New Lines of Code;
Pre-existing SLOC.
New Lines of Code
PRICE-S
INTEGI
CPLX1
PRICE-S
CPLXM, CPLX1
DSTART, PEND
Standard
PRICE-S
UTIL, APPL
PLTFM
PRICE-S
Raw SLOC
NEWD, NEWD, SLOC
SEER-SEM
PRICE-S
CPLX2
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Concept of “Ceterus Parabus”
Methodology to Extract Cost Driver Information
Cost
Slope = delta Cost/delta (Analyst Experience)
Range = Cost/(Analyst Experience)
Parameter
(e.g. Analyst Experience)
Other parameters
held constant
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Major COCOMO Cost Drivers
COCOMO II - Local Impact
(about Baseline, +/- 1 setting)
ACAP = High
PVOL= Nom
PCAP= Nom
RUSE= Nom
CPLX= XHigh
DATA= High
TIME= XHigh
PCON= Nom
APEX = High
SITE= Low
DOCU= Nom
TOOL=Nom
LTEX= Nom
PLEX= Nom
RELY= VHigh
SCED= Nom
SECU = High
STOR=Nom
-
0.20
0.40
0.60
0.80
1.00
1.20
Env ironme ntal Factors
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19th International Forum on COCOMO and Software Cost Modeling
1.40
1.60
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis
- Major SEER-SEM Cost Drivers
SEER-SEM 7.0
Security Requirements= “Nom+”
Analyst Applic. Experience = “Nom”
Analyst Capabilities = “Nom+”
Programmer Capabilities = “Nom”
Requirements Volatility= “Hi”
Modern Development Practices Use = “Hi-“
Automated Tool Use = “Nom+”
Process Volatility= “Nom+”
Multiple Site Development= “VHi”
Programmers Language Experience = “Nom”
LanguageType = “Nom”
Specif ication Level Reliability= “Hi”
0% 10% 20% 30% 40% 50% 60% 70% 80%
Local Impact, Percentage
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Major PRICE-S Cost Drivers
PRICE-S - Local Range
INTEGI-Team=0.70, INTEGETeam= 0.70, CPLX1-person.= 0.2
INTEGI-timing= 0.7,INTEGEtiming=0.7,UTIL=0.5,APPL=8.46
PROFAC= 6.5
CPLXM=1.2
PLTFM = 1.8
CPLX1 -product familiarity
CPLX1-Tools= -0.1, CPLX1Req.+new Lang. = 0
-
0.50
1.00
1.50
Productivity Factors
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19th International Forum on COCOMO and Software Cost Modeling
2.00
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Team & Process
Team
Process
Team
&
COCOMO II
SEER-SEM
PRICE-S
Analyst Capabilities
(1.20)
INTEGI (crew)
(1.58)
Programmer
Capabilities (1.18)
Analyst Experience
(1.21)
PROFAC (1.35)
ACAP (1.41)
PCAP (1.31)
APEX (1.23)
PLEX (1.20)
LTEX (1.20)
Process &
Tools
Programmers
Language
Experience (1.05)
Development
Method –
KnowledgeBase;
CPLX1 – Product
familiarity (1.25)
CPLX1 (1.10)
PVOL (1.99)
PCON (1.24)
TOOL (1.21)
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Process & Reqmts.
Volatility (1.32)
Practices and
Methods
Experience
19th International Forum on COCOMO and Software Cost Modeling
CPLX!-Reqmts.
Volatility (1.13)
CPLX1-Tools
(1.23)
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Market
Market
Market
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COCOMO II
RUSE (1.31)
SITE (1.22)
SECU (1.10)
Schedule
SCED (1.14)
Reliability
RELY (1.15)
Certification
requirements
DOCU (1.22)
SEER-SEM
PRICE-S
CPLXM (1.2)
Security
Requirements(1.75)
Required Schedule;
Start Date
Requirements
Definition Formality;
(part of Platform,
Application -Kbase)
Development Standard Kbase
19th International Forum on COCOMO and Software Cost Modeling
DSTART, PEND
(part of PLTFM)
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Complexity
Complexity
Complexity
COCOMO II
CPLX (1.30)
SEER-SEM
Application (Kbase)
DATA (1.28)
STOR (1.05)
Operating
Environment
Technology
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TIME (1.26)
&
PRICE-S
APPL
UTIL
INTEGI (Timing.
Coupling) (1.55)
Platform; and
DevelopmentMethod KnowledgeBase
19th International Forum on COCOMO and Software Cost Modeling
PLTFM (1.25)
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Scope
Scope b/t Models
COCOMO II
SEER-SEM
PRICE-S
Hardware
developed in
parallel w/
software
System
Integration
Not included
Hardware
Integration Level
(1.09)
CPLX2 (1.20)
Programs
Currently
Integrating (1.04)
INTEGE (1.13)
Not included
Did not find many data points in the COCOMO I
database that suggest a System Integration on the scale
of our (next) Baseline example (3-4 Million SLOCs).
Has COCOMO II been able to collect sufficient data to
develop a (large scale) System Integration factor?
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Economic Properties
(Models Exponents Indicate Diseconomies of Scale for Large Projects)
COCOMO, SEER-SEM, PRICE-S
Effort- Person-Months
20,000
COCOMO
18,000
16,000
y = 19.4 x 1.09
SEER-SEM
14,000
y = 15.1 x 1.12
12,000
10,000
PRICE-S
8,000
6,000
y = 9.7 x 1.11
4,000
2,000
0
100
200
300
400
500
600
KSLOC
The COCOMO II exponent ranges from 0.91 to approximately 1.26 depending upon the Scale Factors.
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19th International Forum on COCOMO and Software Cost Modeling
Model Analysis - Economic Properties
Schedule Variation (SLOC = 50,000)
2,500
2,000
1,500
1,000
500
0
20
40
60
Months
All Software Cost Models show a Schedule Compression penalty.
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19th International Forum on COCOMO and Software Cost Modeling
COCOMO
80
PRICE-S
SEER-SEM
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example
• Illustrate Software Cost Estimation & Integration
– Baseline
– SEER-SEM – Sensor Software
– PRICE-S – Air Vehicle Software
– COCOMO – Control Station
– Sizing Assumptions and Scenarios
– Equivalent New SLOC
– Productivity Range
– Hours/ SLOC
– Estimating Ranges using Monte Carlo
– Hours = (SLOC) X (Hours/SLOC)
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example - Sizing Scenarios (Equivalent New SLOC)
Air Vehicle
Original SLOC point
estimate
2,000,000
Sensor
Original SLOC point
estimate
500,000
Ground Control Station
Original SLOC point
estimate
1,000,000
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Code growth of
-5%, 15%
Code growth of
reuse
15%, 10% reuse
Code growth of
20%, 5% Reuse
SLOC-Low
SLOC-Most Likely SLOC-High
1,615,000
2,070,000
2,280,000
Code growth of
-5%, 20%
Code growth of
reuse
15%, 10% reuse
Code growth of
30%, no Reuse
SLOC-Low
SLOC-Most Likely SLOC-High
380,000
517,500
650,000
Code growth of
-5%, 50%
Code growth of
reuse
10%, 25% reuse
Code growth of
20%, 15%
Reuse
SLOC-Low
SLOC-Most Likely SLOC-High
475,000
825,000
1,020,000
19th International Forum on COCOMO and Software Cost Modeling
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example
– Productivity Ranges
- Productivity (Hours/SLOC)
PRODUCTIVITY
(Hours/SLOC)
Model
Air Vehicle
PRICE-S
Sensor
SEER-SEM
Ground Control Station COCOMO
High
Productivity
Medium
Productivity
3.66
4.02
3.32
Low Productivity
4.48
4.91
4.06
COCOMO Assumptions:
COCOMO – Normalized to include Security, HW/SW integration, System Integration.
This adds approximately 50% to the raw COCOMO II estimate.
The EAF = 3.32 for the Gnd. Cntl. Stn.
The Equivalent New SLOC = 825,000.
The assumed module level was 50,000 SLOC.
The internal integration = 1.05; the external integration = 1.11 for the
“Medium Productivity” (COCOMO) setting.
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19th International Forum on COCOMO and Software Cost Modeling
5.74
6.29
5.20
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example
– Results
Probability
Software - Total Effort
50% Occurs at 15.1 Million Hours
100
90
80
70
60
50
40
30
20
10
0
-
5.00
10.00
15.00
Hours (Millions)
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19th International Forum on COCOMO and Software Cost Modeling
20.00
25.00
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example
– Air Vehicle, Hours = (Hours/SLOC) X SLOC
Probability
SLOC, Thousands Hours/SLOC
Hours, in Millions
0
1625
3.70
6.14
10
1794
4.07
7.83
20
1864
4.24
8.28
30
1914
4.37
8.59
40
1960
4.48
8.87
50
2002
4.61
9.16
60
2038
4.73
9.44
70
2071
4.87
9.76
80
2110
5.03
10.13
90
2164
5.22
10.64
100
2275
5.73
12.48
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example
– Sensor, Hours = (Hours/SLOC) X SLOC
Probability
SLOC, Thousands Hours/SLOC
Hours, in Millions
0
382
4.03
1.66
10
441
4.48
2.15
20
467
4.66
2.30
30
486
4.81
2.42
40
502
4.93
2.52
50
518
5.05
2.61
60
531
5.18
2.71
70
548
5.33
2.82
80
566
5.52
2.94
90
590
5.74
3.13
100
647
6.28
3.99
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19th International Forum on COCOMO and Software Cost Modeling
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19th International Forum on COCOMO and Software Cost Modeling
Baseline Example–Control Station,Hours=(Hours/SLOC)X SLOC
Probability
SLOC, Thousands Hours/SLOC
Hours, in Millions
0
478.8
3.33
1.73
10
608.7
3.69
2.50
20
669.1
3.86
2.75
30
715.4
3.97
2.95
40
753.4
4.07
3.10
50
786.1
4.17
3.25
60
815.8
4.28
3.40
70
845.5
4.40
3.57
80
878.1
4.55
3.75
90
923.3
4.73
3.98
100
1017.1
5.18
5.06
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19th International Forum on COCOMO and Software Cost Modeling
Summary
• Identified Major “local domain” Cost Drivers
– COCOMO II, SEER-SEM, PRICE-S
• Examined Economic Properties
– Diseconomies of Scale, Schedule Compression
– Productivity Ranges
– Scenario Analysis using top 2-3 Cost Drivers
• Illustrated Software Cost Estimation & Integration
– Model Integration using Monte Carlo Probability
Curves
– Scenarios for Sizing
– Model Output for Productivity
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19th International Forum on COCOMO and Software Cost Modeling
Object Oriented Analysis (OOA)
• OOA
– Unified Modeling Language (UML)
– Several Standard Diagrams
– Starts with “Use Case” (users view of the world)
– Develops charts including:
– Use Case (Actors use of information in the system)
– Collaboration Diagrams (provide details of each Use Case)
– Class Diagram
– Specify Blueprints (for objects)
– Attributes and Methods
– Relationship between Classes
– Objects are linked across a design
– Object Interfaces
– Encapsulates Local Variables within a “Black Box”
– Inheritance of Classes
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19th International Forum on COCOMO and Software Cost Modeling
Snapshot of Unified Modeling Language (UML)
– From Use Case, Flow of Information, to Class Diagrams of Systems
Medical System – UML Use Case
Collaboration Diagram
- Make Appointment
Doctor
Login in
Assume successful login.
Cancel Appt
View Patient History
Cancel Appt
:patient
Approve Prescription
Make Appt
Insurance
Patient
Change Doctor
Request
co-pay
1: request appt.
Provide
co-pay
Receive
Authorization
3: send Insur. Co-Pay Amount
:Controller
4: request schedule availability
6: book Appt.
View Patient History
Receive co-pay
Receive notification
:Insur_Obj.
2: request Insur. Co-Pay
Pharmacist
Calc co-pay
Change Location
6: Display/save Appt. results w coPay info. on patient computer
Nurse
Receive Refill
Request
5: display schedule availability
:scheduler
7: confirm Appt.
:Appt._Object
Request Prescription
May 9, 2004 UML Final, Harwick
May 9, 2004 UML Final, Harwick
View Patient History
Medical System UML Class Diagram –Top View
Appointment
Person
Name; Age;
Address; ID
View_Med_Hist()
Cancel_Apt()
Overview - Big Picture
Doctor
Link to Prescription Package
Link to Messaging Package
Patient
Insur.
Prescription
Medical System UML Class Diagram–Appointment View
Patient
Primary_Doctor_Name
Doctor
Nursing Staff
Dept.; Location
Dept; Location
Person
Location
Appoint.
Messaging
Nursing
Medical
Record
Make_Apt()
Chng_Doc()
Chng_Loc()
Req_Prescript.()
Request_CoPay()
Cancel_Apt() *
View_Med_Hist()
Write_Prescript.()
Renew_Prescript.()
Cancel_Apt *
Update_Med_Hist()
View_Med_Hist()
Cancel_Apt *
* An Override method in the subclasses.
May 9, 2004 UML Final, Harwick
10/07/2004
19th International Forum on COCOMO and Software Cost Modeling
May 9, 2004 UML Final, Harwick
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19th International Forum on COCOMO and Software Cost Modeling
Object Oriented Analysis (OOA) Benefits
• Object Oriented Analysis with Unified Modeling Language
– Overall Project Cost Savings
– Similar to System Engineering impact:
– Mitigate Risk, Cost, Schedule Impacts
– Decreases Defects
– May increase Design work
– But Avoids excessive re-work
– Facilitates Integrate and Test
– Better designed Interfaces
– Promotes System Integration
– If compatible UML used on all vendor designs
– Helps Customer Understand Product Purchased
– Sooner, Decrease Requirements Volatility
– Need Data to Measure impact of OOA (UML)
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19th International Forum on COCOMO and Software Cost Modeling
References
•
•
•
•
Models:
Price Systems, PRICE-S model, Los Angeles, California, 1996.
Galorath Associates, SEER-SEM, Los Angeles, California, 1996.
USC Associates, COCOMO II.1999, Los Angeles, California, 2004.
• Books:
• 1. Boehm, Reifer, et al., Software Cost Estimation with COCOMO II,
Prentice-Hall, New Jersey, 2000.
• 2. Boehm, Barry W., Software Engineering Economics, Prentice-Hall, New
Jersey, 1981.
• 3. Deming, W. Edward, Out of the Crisis, Massachusetts Institute of
Technology, Cambridge, 1982.
• 4. Cs3 Inc., Objected Oriented Analysis Using the Unified Modeling
Language, (UML), Los Angeles, CA, 2000-2003.
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19th International Forum on COCOMO and Software Cost Modeling