Paper discussion: Bacchelli and Bird [1]

We discuss the paper “Expectations, outcomes, and challenges of modern code review[1] by A. Bacchelli and C. Bird


  • Appeared at ICSE 2013
  • Very strongly cited
Citations over time

Citations over time


  • Alberto Bacchelli is a prof at the University of Zurich (former TU Delft)
    • Extensive work on all aspects of code review
    • Also work on commmunication and team work
    • Intern at Microsoft
  • Christian Bird is a researcher at Microsoft Research Redmond
    • Multifaced work on how software teams work together
    • Started with OSS communities, Microsoft-centric etc
    • Also, work on code analysis


  • Git revolutionalized not just version control, but also code review
  • Code review is (was) changing: From rigid processes, we go to per commit or per feature changes
  • We don’t know the processes that emerge and the challenges that developers face
  • We need to discover them to inform the design of tools

Research method

We started without a priori hypotheses…:

  • observed 17 industrial developers performing code review
  • interviewed these developers using a semi-structured interviews
  • manually inspected and classified the content of 570 comments
  • surveyed 165 managers and 873 programmers

This is called a grounded theory approach

Research method schematically