Interesting novel, published by Eliyahu M. Goldratt in 1997 - “Critical chain”.

I would summarise a book by three statements:

• the production chain is as weak as the weakest link;
• time buffer should be shared among a production chain (Sprint) but not added to each link (Story);
• use the highest chance completion probability for time estimation.

The author suggested creating a time buffer that will be a shared amount for team members. For example, if a team has a 2 weeks sprint, you are estimating tasks for 80% of sprint time, another 20% will be shared among team members when they are failing to deliver in time.

Tasks should be estimated with a time that corresponds to the highest chance of being finished. For example, the task will be definitely done in 5 days, but most likely, if everything will be fine — in 3 days, that is a correct estimate.

Production chain, in modern terms, is a classic example of streams and back-pressure.

Pretty similar concept described by Andrew Grove in “High Output Management”, with “Egg Factory” restaurant and processing pipeline where making eggs was a limiting step.

I think this method could really work, especially in outsourcing