How is it possible?

It’s all in the planning.

There are three principles that underlie everything that Fast Projects does and that make the shortening of projects possible. These are:

Principle #1: Planning is good.
If you’re in any doubt about this, read https://fastprojects.org/2017/08/23/we-dont-have-time-to-plan-it-just-go-do-it/ and if you’re still not convinced then there’s no point in reading any further.

Principle #2: Detail is good.
When we teach project management, we teach people to break their projects down to elements / tasks / ‘little jobs’ which are in the range 1-5 days duration or 1-5 person-days effort. (While there are exceptions to this, it’s true in most cases).

Principle #3: If detail is good, then more detail is really good.
If you want to shorten your project, you must spend every day wisely. Another way of saying this is that you need to break things down to the day / person-day level of detail. Master this idea and you’re in business. All of the Fast Projects techniques are about spending every day wisely.