Property taxes are a common revenue source for city governments. There are two property tax bases available--land value (site value, SV) or total property value (capital improved value, CIV). The choice of property tax base has implications for both the distribution and efficiency of the tax. We provide new evidence in favour of SV being both the more progressive and efficient property tax base. First, we use three Victorian datasets at different levels of geographic aggregation to model the SV-CIV ratio as a function of various household income measures. At all three levels, a higher SV-CIV ratio occurs in areas with higher incomes, implying that SV is the more progressive property tax base. Our range of results suggests that a one percent increase in the income of an area is associated with a 0.10 to 0.57 percentage point increase in the SV-CIV ratio. Second, we use historical council data to conduct a difference-in-difference analysis to compare the effect of switching from a CIV to SV tax base on the number of building approvals and value of construction investment. We find that switching from CIV to SV as a property tax base is associated with a 20% increase in the value of new residential construction. This is consistent with the view that changes to land value tax rates are non-neutral with respect to the timing of capital investment on vacant and under-utilised land, which we also demonstrate theoretically.