Feedback Loops for Software Delivery and how to become 6 orders of - PowerPoint PPT Presentation

Feedback Loops for Software Delivery and how to become 6 orders of magnitude more productive Gojko Adzic | @gojkoadzic | https:/ /gojko.net | Software Craftsmanship London 2019

Is it working? instapoll.me/992

Studied electrical engineering? instapoll.me/993

Feedback loops allow us to control systems with very complex dynamics using something much much simpler

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Feedback loops allow us to control systems with very complex dynamics stuff we don't fully understand using something much much simpler with stuff that fits into our heads

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The principle of feedback: Base correcting actions on the difference between desired and actual performance Feedback Systems, K. Aström, R. M. Murray

A £75m “Agile” BBC IT project has evaded scrutiny because managers could make up the benefits as they went along... https://www.theregister.co.uk/2016/05/10/nao_bbc_projects_agile/

A loop without feedback is just RUNNING IN CIRCLES !

TDD leads to good design instapoll.me/996

we tried TDD but... » tests were hard to write » tests are too slow » the architecture/design still ended up bad

Scrum's not working... ...we still have all these problems...

http:/ /buzz.money .cnn.com/2012/08/02/knight-trading-loss/

Feedback without an action is not a loop! It's bad news.

Experts are fine with feedback ... Beginners need actionable advice

Drawbacks of feedback loops » create inherent coupling between parts of a system » can introduce instability if not designed properly » cost and complexity of embedding sensing and actuation Feedback Systems, K. Aström, R. M. Murray

Beware of coupling things through feedback! https:/ /www.wired.co.uk/article/revolut-trade-unions-labour-fintech-politics-storonsky

“People are good at tailoring their behavior to things they are measured against” Cem Kaner Don’t Use Bug Counts to Measure Testers, ST&QE 1999, http:/ /kaner.com/pdfs/bugcount .pdf

Instability » measuring the wrong thing » measuring the right thing in a bad way » long loops, delays and oscillations » runaway behaviour

Do you run A/B tests in production? instapoll.me/997

“162 - 480 LOC per staff month” Capers Jones - Economics of Software Quality

https:/ /ieeexplore.ieee.org/document /6127846

The value of measuring a variable is usually inversely proportional to how much measurement attention it usually gets Measurement inversion, Douglas Hubbard - How to measure anything

People measure crap that's easy, not stuff that's valuable

Do you use automated client-side error tracking (Sentry, Rollbar, crash analytics...)? instapoll.me/994

Answer Responses Not tracking errors 53% Web analytics 15% Sentry 15% TrackJS 4% Rollbar 3% https:/ /gojko.net /assets/201802-js-research.pdf

How frequently do you observe actual users working with your software? instapoll.me/995

https:/ /gojko.net /2016/03/14/most-important-lesson/

The faster the feedback, the more intuitive the controls

not possible ⇒ expensive but... does it inform an important decision?