Measuring the Progress of Projects Using the Time Dependence of Code Changes

Omar Alam, Bram Adams and Ahmed E. HassanSoftware Analysis and Intelligence Lab (SAIL), Queen’s University, Canada

1

Tracking the Progress of Projects

2

Managers track projects through:

Manually compiled progress reportsMeetings with developers

Software as a Construction Project

Each change provides structure which other changes can build on

3

Approach: Establishing Time Dependence Between Changes

Time dependent Time dependent

4

Approach: Establishing Time Dependence Between Changes

C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11

Time Dependent

Time Dependent

Time DependentPeriod1 Period2 Period3

5

Approach: Establishing Time Dependence Between Changes

C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11

Time Dependent

Time Dependent

Time DependentPeriod1 Period2 Period3

Time Dependent

Time Dependent

6

Approach: built-on-new, built-on-old and independent changes

Built-on-old

Built-on-new

C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11

Time Dependent

Independent

Time Dependent

Time Dependent

Time Dependent

Time Dependent

Period1 Period2 Period3

7

Categories of Changes

8

Built-on-New

Independent

Built-on-Old

Case Study

1997-2007

1994-2005 9

Definition of built-on-new and built-on-old

The average plateaus when moving to periods longer than two quarters

10

Just-in-time or Delayed?

?

11

Q1 How does the Time Dependence of Changes Vary?

Q1 : How does the Time Dependence of Changes Vary ?

12

PostgreSQL

Built-on-New Built-on-NewBuilt-on-Old

FreeBSD

13

Skyscrapers or Urban Sprawl

?

14

Q2: What is the Impact of Independent Changes?

Q2: What is the Impact of Independent Changes?

15

PostgreSQL

FreeBSD

16

Construction or Renovation?

same floor or different floors?

17

Q3: Is the Distribution of Time Dependence Similar for the Regular Development and Bug Fix Processes?

Q3: Is the Distribution of Time Dependence Similar for Regular Development and Bug Fix Processes?

Correlations between bug fix and enhancement changes

PostgreSQL FreeBSDBuilt-on-New 0.87 0.81Built-on-Old 0.90 0.91Independent 0.84 0.90

18

Same or Different Floors?

PostgreSQL and FreeBSD

19

Risks of Construction?

20

Q4: Is building on new code risky?

Q4: Is Building on Recent Changes Risky?

Correlation is 0.91 for FreeBSD21

years

Q4: Is Building on Recent Changes Risky?

Correlation is 0.65 for PostgreSQL

22

years

Is Building on New Code Risky?

Building on new code is risky

Yes

23

24

PostgreSQL FreeBSD

Built-on-New Built-on-NewBuilt-on-Old

Fewer independent changes More independent changes

Conclusion

25

Building on New Code

Risky and leads to bugs

Regular Development and Bug Fix

On same change periods

Conclusion