Don't they get lazy ?

During a project done the Evo way, I got (via, via) a remark questioning the productivity of the method:
We all understand the concept that if you give someone a task of 3 days and give him 5 days for it, it will take 5 days. This is also known as Parkinson's Law: "Work expands to fill the time available". Management know this concept very well and use it in a different way: If you give someone a task of 6 days and give 5 days to do it, it will take 5 days. Bingo! That's productivity! Unfortunately, although intuitively it seems correct, this is not true. If you ask impossible things from people, they don't even really try to do it. And because they continuously fail to accomplish success, motivation dies. And motivation is the motor of productivity.

By organising about 3 days effort (we start default with 2/3 of the gross available time) in 5 days lead-time, people can and will commit to the tasks planned and will deliver, or at least learn, within about 3 weeks, what they can deliver, 100% done. To illustrate the concept of 100% done I say: "Even if you promise to deliver nothing, as long as that is 100% done." Before trying to optimize what is done, we should first learn to understand what 100% done really means. After all, if someting isn't 100% done, it's not done. People learn within a few weeks estimating what they can really accomplish in a given amount of time. Now real planning and tracking becomes possible. And don't forget: people are not lazy! Otherwise they would have chosen an other job. Just help them to do the job right.

This only works if we let the people self decide what amount of work they will deliver. As long as management asks more than people can commit to, management will get less than possible. If people get the opportunity to deliver what they have committed to, motivation returns. Smiles return. People get relaxed. They make less mistakes, saving valuable time: real productivity is back again. If we give them 3 days effort for 5 days lead-time, we get a higher productivity! Quality is cheaper! Now, what are they doing in the other two days? In the other two days, they do all the things they didn't plan, but will do anyway, like helping each other, meeting, socializing, getting coffee, going to the bathroom, etc. Recently, we reformulated this concept a bit, saying: