Cost Per Square Foot

• Measured for livable space (cost to build the complete home / sf of livable space only) only as the claimed industry standard of measuring cost of a home. Thus, a large garage and porch or upscale interior finish drive the cost up [1]. Does not include land.
• Average USA cost is $150 builder grade [2]. But this figure is different than the industry standard cost method - here they don't include land NOR non-livable space such as garage. Thus, the Forbes definition is not the standard definition.
• So which is it?