Gap = (Actual Index Level - Mean Pre-Bubble Ratio) / Actual Index Level

The ratio of the S&P/Case-Shiller Home Price Index Level to the rent index level. The rent index is based on CPI Rent of Primary Residence (NSA) data as reported by the U.S. Bureau of Labor Statistics. The U.S. Home Price-to-Rent Gap is the percentage difference between the current level of the ratio and the mean, pre-bubble ratio. The pre-bubble mean ratio is derived by from data from 1987 through 1999.