At the request of Housing Division, three categories of Housing Vacancy Survey (hereafter referred to as 'HVS') series were studied; rates of Rental Vacancy, Homeowner Vacancy, and Homeownership. A total of fifteen quarterly series were studied - each of the three HVS categories at the national and regional (North East, North Central, South, and West) levels.

In the first part of this report, we will summarize our 9 findings. We will then discuss "Sliding Spans", a technique used to evaluate the reliability of a seasonally adjusted series. Next, we will illustrate some of the differences in the original and seasonally adjusted series with two graphs. Finally, we will address the issue of making statistical comparisons in unadjusted and seasonally adjusted data.