This document discusses different techniques for validating data models, including verification versus validation, why and what to validate, the base of validation, and specific validation techniques. The key techniques discussed are team review, simulation, direct application, and testing. Team review involves both formal and informal peer review steps. Simulation validates the model by simulating real-world conditions. Direct application builds and tests a model in stages. Testing establishes a baseline and uses a test-driven approach to validate changes.

1. Data
Validation
CHAPTER 7

2. What’s the difference?
• Verification
 Are you building the product right?
 Software must conform to its specification
• Validation
 Are you building the right product?
 Software should do what the user really requires
Qamar Wajid Ali
2

3. Why & What to Validate ?
How ?
What ?
Why ? Common Mistakes
Contents
Complete Correct
Utility
Concise
Qamar Wajid Ali
3

4. Base of Validation ?
Effective Model
Maintainability Utility
Correct Model
Accuracy Completeness
Balance
A model achieved its purpose if questions are answered by the model it self
Qamar Wajid Ali 4

5. How to Validate ?
Basic four techniques are
1. Team Review
2. Simulation
3. Direct Application
4. Testing
Qamar Wajid Ali
5

6. 1. Team Review Validation
Formal
•Modelers
•Reviewers
•Direct Feedback
•Rework the Model
In-formal
•Lunch
•Hallways
•Workstations
•Casual Settings
Localized
• Distributed
• Problem & Fix
• Debate Session
Qamar Wajid Ali 6

7. 7
1.1 Typical Review Steps (1)
▪ Plan review
▪ The review team is selected and a time and place for the review meeting is chosen
▪ Distribute documents
▪ The requirements document is distributed to the review team members
Qamar Wajid Ali

8. 8
1.1 Typical Review Steps (2)
▪ Prepare for review
▪ Find conflicts, omissions, inconsistencies, deviations from standards, and other problems
▪ Hold review meeting
▪ Individual comments & problems are discussed and a set of action to address the problems
Qamar Wajid Ali

9. 9
1.1 Typical Review Steps (3)
▪ Follow-up actions
▪ The chair of the review checks that the agreed action items have been carried out
▪ Revise document
▪ Requirements document is revised to reflect the agreed action items
▪ At this stage, it may be accepted or it may be re-reviewed
Qamar Wajid Ali

10. 1.2 Typical Review Questions
▪ Stakeholders Needs
▪ Correct Stakeholders been Identified?
▪ Sufficient Model views to meet each stakeholder`s need?
▪ Well organized to permit rapid access to information?
▪ Model Construction
▪ Sufficient mappings?
▪ Assumptions been noted and justified?
▪ Strength and Weakness of the model?
▪ Model Contents
▪ Internally Consistent?
▪ Information Updated, correct and Complete?
▪ Relevant data been overlooked or incorrectly interpreted?
Qamar Wajid Ali 10

11. 2. Simulation Validation
Data on Webserver
Router
Application Servers
User GUI
Qamar Wajid Ali 11

12. 2.1 Simulation Model V & V in the Modelling Process
Source: http://www.informs-sim.org/wsc97papers/0053.PDF
Qamar Wajid Ali 12

13. 3. Direct Application
Benefits
▪ Built in Stages
▪ New Experiments
▪ No Harmful Effects
 Executed
 Exercised
Process
A
Process
B
Process
Z
Software
Drawbacks
▪ Can not be executed in stages
▪ No live Experiments
▪ Harmful Effects

14. 4. Test Based Verification
 Base line
 Internal Control
 Limitations
Add a Test
Run the
Test
Make little
change
Run the
Tests
(Pass)
(Fail)
(Fail)
(Pass,
Development
Continues)
(Pass,
Development Stops)
(Start)