Software estimates have never worked and never will

David Heinemeier Hansson argues that software estimation has consistently failed since the inception of computing, particularly for medium to large projects. He contends that as software development becomes routine, it transitions into products or services that can be purchased rather than built. Most software development today focuses on novel work, which is inherently unpredictable, making upfront specifications ineffective. Past attempts to define novel work have often resulted in solutions that do not address real problems, leading to a cycle of misdirection and rework. Hansson advocates for abandoning traditional estimation methods in favor of a budget-based approach, as outlined in his Shape Up methodology. He asserts that programmers can deliver quality software on time when the scope remains flexible during development. This approach allows for necessary trade-offs and adjustments, ultimately leading to better outcomes. Hansson emphasizes that successful software development is about adapting to human nature and understanding that initial requests often stem from a limited grasp of the problem.

- Software estimation has historically failed for medium to large projects.

- Routine software development becomes purchasable products rather than custom builds.

- Novel work is unpredictable, making upfront specifications ineffective.

- A budget-based approach can lead to better software delivery.

- Flexibility during development allows for necessary trade-offs and improved outcomes.