Page 451 - Invited Paper Session (IPS) - Volume 1

IPS176 Thomas A. K.
Rental housing does not only comprise multi-family dwellings but also
extends in part to houses or individual apartments in condominiums. The
prices of (detached) houses, terraced houses and apartments in 127 towns and
cities are collected by bulwiengesa using a detailed and structured annual
questionnaire among local contact persons (e.g. real estate agents, real estate
experts at banks, project developers, investors etc.). The outcome of the survey
are assessments of transaction prices for typical objects which are
characterised in terms of size, location, age, fixtures and fittings, and other
price-determining factors. The bulwiengesa experts ensure a careful data
validation and form valuations which are representative for houses, terraced
houses and apartments in the 127 towns and cities. As characteristics are kept
constant over time, the valuations refer to objects of a constant-quality and
can thus be interpreted as appraisal prices.

b. Data on the floor space of commercial real estate in 127 German towns
and cities
The data on the floor space of commercial real estate is composed by three
sources. For rental housing, the 2011 census information is used. Office space
is taken from bulwiengesa, and retail space in the 127 towns and cities results
from estimates on the basis of official county level data.
The stock of dwellings as existed on 9 May 2011 (i.e. reporting date of the
census) is reported in great detail. The tabulated information suits to form the
aggregates needed for the derivation of weighting schemes. One crucial
breakdown is along the number of housing units in dwellings. This piece of
information makes it possible to distinguish between houses (i.e. dwellings
with one unit or two) and multi-family dwellings (i.e. three and more units).
With the additional information about whether multi-family dwellings are
condominiums or owned by single legal entities, it is able to separate out the
number of apartments which can be transacted individually. Information about
the legal status of the owner help distinguish between dwellings which are
either in the hands of private households or private enterprises including
housing cooperatives. Dwellings owned by the public sector are not
considered in the calculations here due to the supposition that this could be
social housing to a large extent. The census also provides information about
the primary use of dwellings, yielding a distinction between owner-occupied
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housing and buy-to-let. A categorisation of housing units in dwellings
according to their floor space finally enables to account for the fact that

Additional categories of minor relevance are holiday homes and vacant homes. While the
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former are split fifty-fifty between owner-occupied and rented out, the latter are completely
assigned to rental housing as the owners of vacant homes are assumed to live somewhere else.
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