Overall, the time to release the same feature with tests was less than it was without tests. The teams were roughly at the same skill and experience level and the features were roughly the same to implement.
Still, the managers on the team with the unit tests didn’t initially believe the pilot would be a success. The reason is that they only looked at the first row as the criteria for success in the project instead of the bottom line. In the first line, it takes twice the amount of time to code the same feature (unit tests cause you to write more code, naturally. It doesn’t matter that the time “wasted” more than made up for itself when the QA team got a hold of the product and found less bugs to deal with.
That’s why it’s important to emphasize that unit testing can increase the amount of time it takes to implement a feature but that time balances out based on quality and maintainability over the product’s release cycle.