1. Software Dependencies, Work Dependencies,
and their impact on Failures
Jeffrey A.Roberts, James D.Herbsleb, Marcelo cataldo and Audris Mockus
Presented By
Muthukumaran Kasinathan

2. Introduction
“Software faults are often the result of violated dependencies
that are not recognized by developers implementing software”
Research Questions
 What is the relative impact of syntactic and logical
dependencies on the failure proneness of a software
system?
 Do higher levels of work dependencies lead to higher levels
of failure proneness of a software system?

3. Software Dependencies
 Syntactic Dependencies
 Logical Dependencies
 Work Dependencies

4. Syntactic Dependencies
“Syntactic dependencies will be computed between source
code files by identifying data, function and method references
crossing the boundary of each source code file ”
 Focuses on Control and Dataflow relationships
 These dependencies could be:
 Inflow, Outflow Data Dependencies
 Inflow, Outflow Functional Dependencies

5. Logical Dependencies
 Relate source-code files that are modified together as part of
an MR
 If only one file was changed for an MR, then there is no
dependencies
 Using the Commit information from the Version control
system, a logical dependency matrix (LDM) was created
 LDM is a symmetric matrix of source-code files where Cij
represents the sum, across all releases, of the number of
times files i and j were changed together as part of an MR

6. Logical Dependencies
“Logical Dependencies between the source code files will be
calculated by identifying source code files that are changed
together as part of software development”
 Identifies important dependencies that are not visible or
covered in Syntactic Dependencies.
 These dependencies could be:
 Number of Logical Dependencies
 Clustering of Logical Dependencies

7. Work Dependencies
 Impact of human and organizational factors on the failure proneness of
software systems
 Impact of Lack of proper communication and coordination between developers
 Identification and management of work dependencies
 These dependencies are:
 Workflow Dependencies
 Coordination Requirements

8. Data Collection
 Examined two large software development projects:
 Project A
 Complex distributed system
 Data are covered for 3 years of development activity
 The company had 114 developers grouped into 8 development team
and has 3 development locations
 ≃ 5 million lines of code distributed in 7,737 source code files in C
language
 Project B
 Embedded software system
 40 developers in the project over a period of 5 years
 1.2 million lines of code developed in both C and C++ language

9. Data Collection
 In both projects, every change to source code was controlled
by Modification Requests (MR)
 Every change made to Source code has to be committed to
Version Control System
 Information Used for this Analysis:
 Collected a total of 8,257 and 3,372 MRs for Project A and
Project B
 Version control system from both projects
 The source code itself from both projects

10. Measuring Failure
 Goal is to investigate failure proneness at the file level
 File Buggyness – indicates whether a file has been modified
in the course of resolving a defect

11. Results
 Analysis consists of two stages:
 First Stage: Focus on examining the relative impact of
each dependency type on failure proneness of source-
code files
 Second Stage: Verified the consistency of the initial
results by conduction a number of confirmatory analysis
 Constructed several logistic regression models

12. Results
 Model I:
 Based on LOC and Average Lines Changed
 LOC is positively associated with failure proneness
 Average lines changed is also positively associated with defects
 Model II:
 Introduces Syntactic Dependency measures by:
 Inflow Data
 Has significant impact on error proneness
 Inflow Functional
 This type of syntactic dependency has less impact on failure
proneness

13. Results
 Model III:
 Higher number of logical dependencies related to an increase in
the likelihood of failure
 Model IV:
 Workflow dependencies do increase the likelihood of defects
 Model V:
 Coordination requirement has an higher impact in Project A and
lesser impact in Project B

14. Conclusion
 All dependencies increases fault proneness
 Logical Dependencies has the highest impact, followed by
Workflow dependencies and then Syntactic Dependencies