This sounds like a variation of the Gross Rent Multiplier (GRM). GRM uses 'scheduled' rents as opposed to gross rents, and your value can be determined by the multiplier that similar 'sold' properties in that particular market have been selling at.
The problem with these formulas is that they get altered to satisfy the author of some cash flow analysis. If you want to leard the industry standards, you should attend the 2 day CCIM Intro course. You will learn far more than those 'get rich' books teach.
Aug 29, 2009