Software estimation is the most difficult single task in software engineering- a close second being requirements elicitation.

There are a lot of tactics for creating them, all based on getting good requirements first. But when you're back's against the wall and they refuse to give you better details, Fake It:

1. Take a good look at the requirements you have.
2. Make assumptions to fill in the gaps based on your best guess of what they want
3. Write down all your assumptions
4. Make them sit down, read, and agree to your assumptions (or, if you're lucky, get them to give in and give you real requirements).
5. Now you have detailed requirements that you can estimate from.

It's like my mother used to threaten when I was a kid "Hurry up and pick out some clothes, or I'll pick them out for you!"

Software estimation is the most difficult single task in software engineering- a close second being requirements elicitation.

There are a lot of tactics for creating them, all based on getting good requirements first. But when your back's against the wall and they refuse to give you better details, Fake It:

1. Take a good look at the requirements you have.
2. Make assumptions to fill in the gaps based on your best guess of what they want
3. Write down all your assumptions
4. Make them sit down, read, and agree to your assumptions (or, if you're lucky, get them to give in and give you real requirements).
5. Now you have detailed requirements that you can estimate from.

It's like my mother used to threaten when I was a kid "Hurry up and pick out some clothes, or I'll pick them out for you!"