SE 477
Software and Systems Project Management
Dennis Mumaugh, Instructor
[email protected]
Office: CDM, Room 432
Office Hours: Monday, 4:00 – 5:30
May 3, 2010
SE 477: SERIM Lecture
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Software Engineering Risk Model
(SERIM)
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Software Engineering Risk Model (SERIM)
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Applicable for small and medium sized organizations.
Primarily qualitative with quantitative analysis.
Applicable to full life-cycle including maintenance phase.
Maintainable during project development.
Compatible with any development model, such as spiral,
waterfall, joint application design, recent application
design, incremental, or prototyping.
 SERIM uses risk questions to derive numerical
probabilities for a set of risk factors and analyzes them
using a simple spreadsheet.
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SERIM Terminology
 Risk Elements – Technical, Cost, Scheduling problems.
 Risk Factors – more specific subcategories of the three general risk
elements (for example organizational risk). A risk factor can be
related to one or more risk elements.
SERIM identifies ten primary risk factors of: organization, estimation,
monitoring, development, tools, risk culture, usability, correctness,
reliability, and personnel.
Each software risk factor can have an influence on each risk element.
That influence can be categorized as low, medium, or high.
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SERIM Terminology
The impact of each risk
factor on each risk element.
The effect of risk factors
on each risk categories.
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Risk questions
 One approach to assessing risk is to use risk questions to measure
risk factors.
 Answers to the questions can be recorded in a yes-or-no format (0
or 1) or as a numerical range of possible responses.
 Response ranges can use any numerical value from 0 through 1.
For example, a response range could be defined as none = 0, little =
0.2, some = 0.5, most = 0.8, and all = 1.0.
The
relationship of
risk questions
to risk factors
and risk
elements.
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Organizational questions
O1. Are you using or do you plan to use
experienced software managers?
O2. Has your company been producing
software similar to this in the past?
O3. Is there a documented organizational
structure either in place or planned?
O4. Is the organizational structure stable?
O5. What is the confidence level of your
management team?
O6. Does good communication exist
between different organizations
supporting the development of the
software project?
O7. Are software configuration management
functions being performed?
O8. Are software quality functions being
performed?
May 3, 2010
SE 477: SERIM Lecture
Devise a numerical range
of responses:
For example in question
O1:
1= Mgrs with little or no
SE experience.
0.5 = Mix of experienced
and non-experienced
managers.
0 = Only experienced
managers.
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Calculating P(An) Example Organizational success:
Question
O1
O2
O3
O4
O5
O6
O7
O8
Success
Imp
% of imp
Are you using or do you plan to
use experienced software
managers?
0.5
0.8
0.173913043
Has your company been
producing software similar to this
in the past?
1
Is there a documented
organizational structure either in
place or planned?
0
Is the organizational structure
stable?
0.5
What is the confidence level of
your management team?
0.5
No experience.
0.5
0.4
0.108695652
0.086956522
1 = Yes lots of
experience. 0 = No
experience.
3.previous
Calculate
1
Are software configuration
management functions being
performed?
1
Are software quality functions
being performed?
1
0.5
0.8
0.4
Impact
Total:
0.108695652
0.173913043
0.086956522
0.4
0.086956522
0.8
1. Sum
0.173913043
the
impacts.
Success
Factor
0.086956522
0.108695652
Documented
%1=of
Impact
= No doc.
Xstructure,0
success.
structure.
Does good communication exist
between different organizations
supporting the development of
the software project?
May 3, 2010
2. Calculate
Comments
Imp /
1 = Impact
Experienced, 0.5 =
Mixed
experience, 0 =
Total.
0
1= Stable, 0.5 = Semi
stable, 0 = volatile.
0.054347826
1 = Very conf., 0.5 =
medium conf., 0 = little
confidence.
0.086956522
1 = Good
communication, 0 = No
communication
0.086956522
1 = Yes, 0 = No.
0.086956522
1 = Yes, 0 = No.
0.173913043
4.6
Probability of Success based on these questions: P(An)
SE 477: SERIM Lecture
0.68478261
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Quantitative Risk Analysis
 The probability of a successful project P(A) is derived
using the following equation where E = the number of risk
elements.
E
P(A)  [ P(An )] / E
n1
This equation assumes that all risk elements are equal in
weight. P(A) is the probability of a successful project.
 Ifdifferent risk elements have different impacts (weights),
then:
P(A) =w1P(A1) + w2P(A2) + w3P(A3),
where w1 is a positive number and w1 +w2 + w3 = 1.
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Example:
 5 risk elements at the following probabilities for success:
A1 = 0.9, A2 = 0.75, A3 = 0.85, A4 = 0.6, A5 = 0.95
 Risk elements weighted as:
w1 = 0.2, w2 = 0.4, w3 = 0.1, w4 = 0.1, w5 = 0.2
 Probability for success
P(A) = (0.9*0.2) + (0.75*0.4) + (0.85*0.1) +
(0.6*0.1) + (0.95*0.2)
P(A) = 0.815
 Question: Should we proceed??????
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Journal Exercises
 Discuss SERIM. [No, it is not an Italian vending machine company
with a good cup of coffee.] What is it good for? How does it work?
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