1. Lecture Software Process Definition and Management Chapter 3: Descriptive Process Models
Dr. Jürgen Münch
Fall 2012 1

2. Deviations between Processes
Software Process Definition and Management - Chapter 3
Deviations between Processes
Desired
Process
Descriptive
Process Model
Discrepancies
Actual
Process
Prescriptive
Process Model
Process
Owner
Observed
Process
Perceived
Process
Process
Agent
Stimuli,
Interpretations,
Errors
Results in
Actual Behavior

3. The Importance of Teaching Descriptive Modeling
Software Process Definition and Management - Chapter 3
The Importance of Teaching Descriptive Modeling
 Descriptive modeling is concerned with building useful abstractions of real processes without making assumptions that are not true

4. 8 Steps of Descriptive Process Modeling
Software Process Definition and Management - Chapter 3
8 Steps of Descriptive Process Modeling
Configure the process modeling approach – relatively stable For every process to be modeled
State objectives and scope
Select or develop a process modeling schema
Select (a set of) process modeling formalisms
Select or tailor tools
Elicitation
Create the process model
Analyze the process model
Analyze the process

5. 1. State Objectives and Scope
Software Process Definition and Management - Chapter 3
1. State Objectives and Scope
Goal: Determine the goal(s) of the process modeling and the organizational context
Activities:
Define what the process model will be used for
Identify the intended users of the model
Get to know what the intended users expect from the process model and explicitly state their needs
Identify the granularity of the model
Determine scope, characteristics, and organizational context
Input: -
Output: Process modeling goal

6. 1. Example of a Process Modeling Goal
Software Process Definition and Management - Chapter 3
1. Example of a Process Modeling Goal
Here, for instance, the structure of a GQM goal is used:
Object (Scope):
Review process of a single module
Purpose:
Documentation of the process in order to use it for training
Quality Focus:
Responsibilities and workflow between developers and reviewers
Viewpoint:
Developer and reviewer of a single module
Context:
Software development company XY

7. 2. Select or Develop a Process Modeling Schema
Software Process Definition and Management - Chapter 3
2. Select or Develop a Process Modeling Schema
Goal: Schema that identifies and structures the kinds of information to be captured and their relationships
Activities:
Identify the concepts to be described using the process modeling goals of step 1
Select or develop a schema that supports modeling of the identified concepts
Input: Process modeling goal
Output: Process modeling schema
Example: For the described goal, the schema has to contain
Activities
Control flow between activities
Assignment of activities to roles

8. 3. Select (a Set of) Process Modeling Formalisms
Software Process Definition and Management - Chapter 3
3. Select (a Set of) Process Modeling Formalisms
Goal: Select a process modeling language or notation
Activities:
Select a language or notation that supports the aspects defined in the schema
If not all aspects are covered by a single language: add other languages or notations until all aspects of the schema can be modeled
Keep in mind the possible training effort for learning a new complex language!
Input: Process modeling schema
Output: (Set of) process modeling languages and/or notations
Example: UML activity charts contain all aspects of the defined schema

9. Find tools that support modeling using the defined modeling languages
Software Process Definition and Management - Chapter 3
4. Select or Tailor Tools
Goal: Select or tailor tools that support modeling using the previously defined language(s)
Activities:
Find tools that support modeling using the defined modeling languages
The tools do not necessarily have to be process modeling tools, they can also be simple drawing tools
If necessary, tailor the tools to the specific needs of the languages
For the selected tools, identify the functionality that should be used for modeling
Input: Process modeling languages or notations
Output: Set of modeling tools
Example: Microsoft Visio for modeling activity charts, SPEARMINT for the SPEARMINT process modeling notation

10. Commercial tools without reference to process modeling
Software Process Definition and Management - Chapter 3
4. Modeling Tools
Commercial tools without reference to process modeling
e.g., Microsoft Visio, iGrafx Flowcharter
Workflow management systems
e.g., ARIS Toolset (event-driven process chains)
Research prototypes
e.g., SPEARMINT
e.g., Modeling Support Tool (MoST)

11. Goal: Acquire all information needed to describe the software process
Software Process Definition and Management - Chapter 3
5. Elicitation
Goal: Acquire all information needed to describe the software process
Activities:
Identify all entities (agents, activities, products,…), their relationships, and their properties (e.g., start conditions of activities)
Get information through:
Interviews (used most often)
Observation
Analysis of protocols
Analysis of process documents
Analysis of products
Make sure the process agents do not feel judged or evaluated by the person eliciting! If they do, they will describe an ideal process, not the actual process!

12. 5. Elicitation (continued)
Software Process Definition and Management - Chapter 3
5. Elicitation (continued)
Input: Real process to be modeled
Output: All needed information about the process (interview protocols, observation protocols, process documents,…)
Example:
Interviews with developers and reviewers
Analysis of existing review documents
Analysis of existing documents describing the review process

13. 5. Elicitation: Interviews
Software Process Definition and Management - Chapter 3
5. Elicitation: Interviews
Structured interview, 1 - max. 2 hours
2 interviewers
Interviewees isolated according to roles
no large groups
clear focus
manageable process models
no mutual interaction (horizontal and vertical hierarchical relations)
Perform interviews one after another, however, not more than 3 interviews per day
Role 1
Role n
Information
Information
Steps 6-8
Process
model

14. 5. Characteristics of Example Projects
Software Process Definition and Management - Chapter 3
5. Characteristics of Example Projects
Project A
Embedded real-time system
Engine control
developers
Project B
Time recording system
6-8 developers
6 months development time
Project C
Telecommunication system
400 developers
months development time

15. 6. Create the Process Model
Software Process Definition and Management - Chapter 3
6. Create the Process Model
Goal: Create a process model in the defined language or notation that represents the analyzed process
Activities:
Start by modeling the products
Model activities and product flow
Assign agents and responsibilities to activities
Model behavior (start, end of activities)
Review the process model together with process participants
If necessary, go back to the elicitation step to get needed information
Input:
Process modeling languages or notations (Step 3)
Process modeling tools (Step 4)
Elicited information about the process (Step 5)
Output: process model representing the observed process

16. 6. Example: Process Model for Module Review
Software Process Definition and Management - Chapter 3
6. Example: Process Model for Module Review

17. 7. Analyze the Process Model
Software Process Definition and Management - Chapter 3
7. Analyze the Process Model
Goal: Detect inconsistencies in the model to check whether the model correctly describes the real process and to identify improvement possibilities
Activities:
Static analysis
Completeness (does the model contain all information needed to reach the modeling goal?)
Correctness (is the model free of contradictory information?)
Structural consistency (e.g., are all products used by a refined activity used by at least one of its child activities?)
Dynamic analysis (analysis of behavior during execution)
Identification of deadlocks, ambiguous situations,…
Identification of process weaknesses (critical paths, cost overruns,…)
If an identified inconsistency is due to a misunderstanding of the process, refine the process model
Input: process model; process modeling goal
Output: refined process model; suggestions for improvement

18. 7. Example: Process Model for Module Review
Software Process Definition and Management - Chapter 3
7. Example: Process Model for Module Review
Incomplete model:
Incorrect model:
Correct & complete model:

19. Qualitative analysis: weaknesses of the process
Software Process Definition and Management - Chapter 3
8. Analyze the Process
Goal: Use the process model to track or analyze process performances, depending on the process modeling goal
Activities:
Track the performance of the process by registering starts or endings of activities or by asking developers about their current activities
If necessary, fine-tune the process model with the results of the tracking
Qualitative analysis: weaknesses of the process
For example: Too many responsibilities at one position, excessive feedback loops,…
Quantitative analysis: correlation between process attributes
Input: process modeling goal; process model
Output: depending on goal
Refined process model, improvement options,…
Example: If the goal was to create a process documentation for training, the process model is used to teach new employees the review process

20. Rules of Descriptive Modeling (1/3)
Software Process Definition and Management - Chapter 3
Rules of Descriptive Modeling (1/3)
Obtain information about
the organization
the software domain
Analyze existing documents and products
Check the relationship between developers and quality assurance
Ask whether one of the latest restructurings has had impacts on the process
Make sure that the interview partner is selected according to your instructions / guidelines
Begin the interviews with quality assurance people or project manager

21. Rules of Descriptive Modeling (2/3)
Software Process Definition and Management - Chapter 3
Rules of Descriptive Modeling (2/3)
Process of an interview
Beginning
Summary
Explain goal and purpose
Confidentiality agreement
General questions about the process, specialties
Main part
Behave neutrally
Ask first about products
Then ask about processes
What are typical deviations?
Which other roles participate in the processes? (cross-check)
Always remain precise
Try to identify variants

22. Rules of Descriptive Modeling (3/3)
Software Process Definition and Management - Chapter 3
Rules of Descriptive Modeling (3/3)
Process of an interview (continuation)
Closure
Explain future steps
Adjust the times for the review
Thank your interview partner
Ask questions even when you only identify small ambiguities; often, big problems are hidden behind it
Do not try to solve all ambiguities and conflicts
After the interview: give a quick feedback to the interviewee

23. There exist different purposes of descriptive modeling
Software Process Definition and Management - Chapter 3
Summary
Descriptive process models should explicitly represent the actual process
There exist different purposes of descriptive modeling
Elicitation is the most important sub-step of descriptive modeling
Structured interviews are currently the best practice