There are two types of deadlines:
- Fake deadline: arbitrary date that has no real meaning for the product, the team or the company. Very often it is used only to push a team because management believe that employees dislike work, are lazy, dislike responsibility and must be coerced to perform (Theory X. see McGregor's Theory X and Theory Y).
- Real deadline: A date that can have lot of impact on the success of a product (for example because there are a presentation of other similar products, legislative changes, an opportunity to present the product in an event, a costly advertisement campaign, and so on...)
The real deadlines, are context that should can help the team to make decisions, and it is very important that the team knows this deadline, understands the importance and uses this information to delivery the best result possible for this deadlines. For sure, if the deadline is decided without the input from the development team or is not a deadline for all the people involved in the product, this deadline automatically becomes a fake deadline.
So remember, estimations are only educated guesses, but if someone requires a complete commitment, the team requires absolute control about all the variables and the plan... And this makes no sense.
The only way it's all going to go according to plan is if you don't learn anything— Kent Beck (@KentBeck) 22 de marzo de 2016
BTW: A product so easy to develop than you can design a perfect plan, is a product that shouldn't be created. No risk, No value.