The Impact of Lean and Agile Quantified

This post mean to sum up the key fact you can find analysed on this Larry Maccherone’s talk:

Before to start be aware that:

  • Correlation does not mean causation
  • There are no best practices, only good practices

Iteration Length

  • Teams using two-week iterations have the best balanced performance
  • Longer iterations correlate with higher Quality
  • Shorter iterations correlate with higher Productivity and Responsiveness
  • Some teams are acting like “tough guys” by pretending to operate at one- week iterations when they can’t back it up

Ratio of testers to developers

  • More testers lead to better Quality
  • But they also generally lead to worse Productivity and Responsiveness
  • Interestingly, teams that self- identify as having no testers have:
    • The best Productivity
    • Almost as good Quality
    • But much wider variation in Quality



  • Motive has a small but statistically significant impact on performance
  • Extrinsic motivation does not have a negative impact on performance
  • Executive support is critical for success with Agile
  • Teamwork is not the dominant factor; talent, skills, and experience are
  • Those motivated by quality perform best



  • Teams distributed within the same time zone have up to 25% better productivity
  • Is distraction a problem?


Controlling WiP

  • Teams that most aggressively control WiP have:
    • 50% of the time in process (TIP)
    • 25% as many defects
    • 34% lower productivity


  • If your WiP is high, reduce it
  • If your WiP is already low, consider your economic drivers
    • If Productivity drives your bottom line, don’t push WiP too low
    • If time to market or quality drives your bottom line, push WiP as low as it will go

Estimating process

  • Teams doing Full Scrum have 250% better Quality than teams doing no estimating
  • Lightweight Scrum performs better overall, with better Productivity, Predictability, and Responsiveness


  • Experienced teams may get best results from Lightweight Scrum
  • If new to Agile or focused strongly on Quality, choose Full Scrum


Team stability

  • One out of four team members changes every three months!
  • Stable teams result in up to:
    • 60% better Productivity
    • 40% better Predictability


  • Dedicate people to a single team
  • Keep teams intact and stable


Team size

  • Small teams (of 1-3) people have:
    • 17% lower Quality
    • 17% more Productivity


  • Set up team size of 7±2 people for the most balanced performance
  • If you are doing well with larger teams, there’s no evidence that you need to change