Preliminary remarks

Change History

The following substantial changes have been made in guideline version 1.1, as compared with version 1.0:

  • Section A.2: International Converters for Real Estate Data (ICRED) added.
  • Section 2.1/ Fig. 2/ Tab. 2: New subsets added:
    • 5.5 Benchmarking of operating costs
    • 5.6 Provision of basic valuation data
    • 5.7 Valuation reports

New sections:

  • 3.10 Benchmarking of operating costs
  • 3.11 Basic valuation data
  • 3.12 Valuation

The following changes were made in guideline version 2.0, as compared with version 1.1:

  • Sections 2.1, 3.13/ Fig. 2, Tab. 2: New subset added 5.8 Target fund to fund of funds
  • Section 2.3/ Fig. 3: New entities: contracting party, currency, and securities
  • Section 4.3.2: Reference to knowledge base address
  • Section 4.4.1, Annex H.3 section 2.9: New transfer table: Connection – CONNECTION.csv
  • Annex H.1: Lists of attributes revised, in particular usage types set out with greater detail and consistency
  • Annex H.3 section 2.9: Allocation to individual periods modified
  • Section 1.6: Rule set introduced
  • Subsets 5.1, 5.6, 5.7 amended
  • New data fields (see catalogue version 2.0)

A.1 Background, objectives and target group

A. 1.1 Background and objectives

In recent years, the German real estate sector has developed to meet the requirements of international investors and advance further along the path of specialization. The "real estate" product is undergoing enhancement, with the cooperation of an extensive chain of service-providers. Key success factors for this move toward specialization involve improving the quality of process-based cooperation with and within the service-provider chain, and ensuring the smooth integration of IT systems. Any disruption in the service-provider chain relating to a process, for example due to missing, delayed, or unavailable information, will directly affect the success of this approach. The success factor of good cooperation is to ensure a flow of in­formation that is unambiguous, complete, and of a high quality. It is only possible to define what is unambiguous, complete, and of a high quality based on the objectives of the respective process. The process between investors and service-providers, or between service-providers, runs particularly efficiently if the objectives and content of the information and data exchange are clearly defined, and automated quality checks are in place to ensure that information and data are quickly and effectively exchanged.

Unlike other countries, such as the United States, France, or the Netherlands, until 2014 there was no standard in Germany according to which process-related data
between individual service-providers in the real estate sector is exchanged in a standardized way. Against this background, gif published version 1.0 of the guideline on
the exchange of real estate data ("gif-IDA") in October 2014. Since its publication, gif-IDA has been attracting national and international interest. Many companies apply
the guideline, the underlying data model, and the subsets for exchanging data. Within the real estate sector, there has been growing interest in adding further subsets to
the guideline. gif complied with this request in June 2016 by adding three new subsets for evaluating property and benchmarking operating costs in version 1.1.

Responding to requests from market participants, subset 5.8 Target fund to fund of fund has been added, the entity model has been adjusted, and data fields and lists
of attributes have been expanded in the current version 2.0 of the guideline on the exchange of real estate data.

In this process, each of the three versions of the guideline underwent a green paper phase lasting several months, during which it was submitted to a broad specialist audience for review and comment. All feedback was reviewed by the competence group and incorporated into the respective version of the guideline. The green paper phase was completed by the panel of experts.

A. 1.2 Target groups

This guideline is aimed at all market participants who regularly exchange data for the purposes of designing, planning/construction, purchase, management, and sale of properties and real-estate products, as well as software vendors supporting this process with their products.

A.2 Approach and scope

A. 2.1 Approach

By means of this guideline on the exchange of real estate data, gif Gesellschaft für Immobilienwirtschaftliche Forschung e.V. sets out within a process model all the relevant processes involved in the exchange of data between the individual market participants in the real estate sector. Based on the process model, gif defines all the requisite data fields to ensure successful cooperation. In addition to the process model, a hierarchical entity relationship model (ERM) is also presented, which clearly
assigns client, contracting party, loan, property, land, building, space/ rental unit, lease contract, term, expert reports, projects, currency, and securities to individual data objects. Each data field can be specifically assigned to one or more data objects. To this end, gif focuses on providing a process-oriented and robust definition of the content of the individual data fields, so that the flow of data and information between service-providers involved in a value creation process is unambiguous, complete, and of a high quality. For each process, the actors agree whether they want to exclusively exchange the main core data of the process, which is indicated as "CORE"
or include optional data as well (referred to as "can" data), see section 1.6). In order to make agreements between sender and recipient more accurate, the new subset 5.8 of version 2.0 of the guideline introduces rule sets for the first time (see section 1.6). The use of rule sets will be extended to all subsets in future versions of the guideline.

A. 2.2 XML schemas and IC RED converter

In addition to this guideline, gif also provides XML schemas according to gif-IDA. The XML schemas per data exchange process are intended to enable service providers and software vendors to exchange data for the individual processes and exchange the respective versions of gif-IDA such that the high quality of the exchange is ensured and maintained. In addition to the XML schema,gif provides the International Converter for Real Estate Data (ICRED). The ICRED enables mapping to other exchange formats, such as ValXML (BIIS) , or to the French FIDJI, as well as the automated checking or validation of the schema. The converter can be obtained at here.

A.2.3 Scope of document exchange

Version 2.0 of the guideline is limited to the pure exchange of data and does not include the underlying documents, such as lease contracts. However, the XML schema is
designed such that documents and records can also be supplied as part of a specific process.

A.2.4 Other initiatives and standards

gif observes various standardization initiatives both nationally and internationally and is actively involved in their harmonization. The most significant initiatives are explained below:

At the national level, the following initiatives are worth mentioning:

  • OpenImmo: The Verein zur Förderung des Datenaustausches in der Immobilienwirtschaft e.V. (Association for the Promotion of Real Estate Data Exchange – was established in 2001 with the aim of standardizing the online exchange of real estate data. The data standard, which is mainly intended for software vendors and web service providers, can be obtained from the above-mentioned website. For version 1.2 and higher, a license is required to use OpenImmo.
  • GEFMA: In 2017, the German Facility Management Association, GEFMA e.V. ( published a draft of Guideline 470 "Austausch digitaler Daten im FM – Grundlagen und technische Einordnung" (Exchange of digital data in FM – basic principles and technical placement). The guideline provides an overview of the requirements and usable technologies for exchanging data during the operational and usage phase.
  • ARGE Heiz- und Wasserkostenverteilung: The Arbeitsgemeinschaft Heiz- und Wasserkostenverteilung e.V. (Working Group on Heating and Water Charges Allocation – is a Germany-wide association of leading metering service providers. Together with the Fachvereinigung Heizkostenverteiler
    und Wärmekostenabrechnungen e.V (Association of Heating Cost Allocation and Statements Specialists –, it has developed two guidelines on standard and full exchanges of meter data for utility consumption for heating and water. The aim is to exchange data on a fully electronic basis when preparing and creating statements of consumption charges. Accordingly, data is exchanged in the following data records when data is captured for the statement of heating and water charges and the statement is produced:
    • A record: Basic information on data exchange such as customer and contractor
    • L record: Basic information on property or asset
    • M record: Data on property users/tenants
    • B record: Costs associated with the property
    • K record: Information on invoices and costs
    • D record: Usage data and billing results
    • E-835: Information on tax payments
    • E-898: Transfer of images on billing results
  • GAEB: The Gemeinsame Ausschuss Elektronik im Bauwesen (Joint Committee for Electronics in the Construction Industry – GAEB, has defined as its objectives to promote the rationalization of the German construction industry through a modern IT infrastructure. In this context, GAEB is responsible for drafting and revising
    • the Standardleistungsbuch Bau (Standard Services Book for the Construction Industry – STLB-Bau) with standardized texts for describing construction services for new buildings, maintenance and restoration,
    • the Standardleistungsbuch (Standard Services Book) with standardized texts for describing construction services for work performed under fixed-term
      contract (STLB-BauZ),
    • rules and regulations for electronic data exchange and the creation of the specification (GAEB DA), and
    • process descriptions for electronic volume and construction service billing (GAEB-VB).

The data interchange under GAEB differs in relation to the following phases and exchange processes:

  • X31 Volume determination
  • X80 Performance directory catalog
  • X81 Performance specification
  • X82 Cost estimate
  • X83 Request for tenders
  • X84 Submission of tender
  • X85 Alternative quotation
  • X86 Contract award (incl. addenda)
  • X89 Invoice

Software firms can have their products certified in accordance with GAEB by the German Construction Software Association (Bundesverband Bausoftware e.V. – BVBS, for the areas of "Construction" (Bauausführung) and "Tender, Award, Invoicing" (Ausschreibung Vergabe Abrechnung, AVA).

The following standards have established themselves at the international level:

  • FIDJI: The Format d'Inter Échange de Données Juridiques & Immobilières, (FIDJI, is a standard developed and established in France with the intention of standardizing data exchange among different French market participants.
  • INREV: The European Association for Investors in Non-Listed Real Estate Vehicles (INREV, was founded in 2002 with the aim of establishing reporting and other standards, gathering and publishing market data, and to establish this data through appropriate training and other events.
  • REDEX: The Dutch Real Estate Data Exchange (REDEX, association was founded in 2011 with the aim of optimizing data exchange among the participants of the Dutch real estate market under the OSCRE standard. To this end, REDEX operates its own webbased data exchange platform focusing on
    portfolio management reporting and valuation.
  • OSCRE: The Open Standards Consortium for Real Estate (OSCRE, is a non-profit association with activities in North America and the United Kingdom; it has developed its own standard and supports its implementation.

In May 2016, gif, together with FIDJI, INREV, OSCRE, and REDEX established the International Real Estate Data Exchange Council (IREDEC). The Investment Property
Forum (IPF, and the Royal Institution of Chartered Surveyors joined in February 2017. IREDEC has set itself the objective to harmonize the national data
exchange standards.

A.2.5 Versioning and withdrawal of guideline

This guideline and subsets are updated bythe gif competence group real estate data exchange, and version numbers are allocated to any guideline and subset updates. Significant amendments compared with previous versions are documented in the change history section at the beginning of the guideline.The guideline and subsets may be withdrawn by gif for good cause. An example of good cause includes technical progress in hardware and software development.

A.3 Outlook

This version 2.0 of the guideline is based on the requirements of the German real estate market. A standard has been defined for the structured exchange of data for the core
processes of management, purchase, and sale, in which the largest volumes of data are exchanged.

In subsequent versions, the guideline is intended to be successively expanded to include further real estate-related processes, and extended so that the documents corresponding to the respective processes are also supplied. In cooperation with the IREDEC members, there are plans to take into consideration requirements from other
countries and incorporate a system of mapping with existing guidelines in cooperation with other associations and organizations, and to extend the ICRED converter accordingly. The foundations have been laid for such developments, by preparing the guideline and data model in bilingual format (German-English), and incorporating transformation options with other standards.

The current version 2.0 of gif-IDA does not include a data exchange of files within a subset or a data field, even if this is technically feasible. The exchange of files or
document types, such as a lease contract, invoice, or service contract, e.g., as a pdf file, is planned for an future version of the guideline. The data model is restricted to the main types of real estate usage, i.e., office, retail, storage, and residential. In future, the data model is to be extended to include retail revenue trends or service charge billing
structures, with a view to meeting future requirements, such as utilization of hotel properties.

There are plans in the future to assign a quality label or certificate for software products to individual core processes. To this end, the software vendors must have successfully demonstrated that they comply with the regulations set out in gif-IDA.