The term is generally used by financial, technical professionals and project managers to describe a solid assumption of a numeric target. It is far more than a guess or even a good guess. One is attempting to accurately estimate a number associated with for example a budget or time requirement using the available limited data or in the worse case no data.
If the individual offering the SWAG
projection is well recognized and qualified in his area of expertise and he is offering it within that expertise, the
likelihood that the SWAG will be taken seriously is high, especially if he has a proven
track record.
Someone when challenged on where he came up with his numbers says "well its a SWAG" and he lacks the
credentials to support it, is not likely to be taken seriously. In other word, some people use SWAG as a casual term instead of saying I guess.
Example:
When challenged to project the budget for a project whose concept is new to the organization, a scientific-wild-ass guess (SWAG) may be the only means of generating
a realistic set of numbers.
Consult experts in the various areas that may be involved. Example: A new product that has a market pull but has no material, manufacturing processes or facilities but needs to be brought
on line within a set period of time, will by necessity require some SWAG. Having a SWAG number helps to provide guidance even if it is not totally accurate. It is far better than having an open checkbook.