The BIRD methodology refers to the technique used to provide a formal documentation of the BIRD proposed data model.

The description of the BIRD proposed data model is composed of:

  • Description of datasets
  • Transformation process
  • Technical guidelines on how to populate the datasets and implement transformations.

The BIRD is documenting a dynamic data process, where some data are provided as input, validated and subsequently transformed into other datasets until the final datasets are generated. These datasets reflect the secondary reporting, i.e. the information that NCBs need to provide to the authorities (e.g. the ECB or the EBA).Section 2 of this document describes the high-level BIRD data process.

The BIRD provides a formal description of both the datasets and the validation and transformation rules. Section 3 introduces the methodology for the formal description of the BIRD datasets, while section 4 deals with the validation and transformation language.

The technical guidelines on how to populate datasets, which include the conceptual model of the relation between the cubes in the form of an Entity Relationship Model, constitute a separate document, the BIRD technical guidelines, which is included in the BIRD website.

High-level BIRD data process

The BIRD data process may be divided into four layers and three phases separating those layers. The four layers are:

  • The Input Layer (IL)
  • The Enriched Input Layer (EIL)
  • The Reference Output Layer (ROL)
  • The Non-reference Output Layer (NROL)

While the three phases may be denoted by

  • Phase 1 (IL -> EIL)
  • Phase 2 (EIL -> ROL)
  • Phase 3 (ROL -> NROL)

Please note that the layers are described by Cubes while the phases are described by Transformations and Mappings in the BIRD data base.


The Input layer

Represents a harmonized entity relationship model (ERM) that comprises the necessary information that is available in bank’s internal systems in order to generate the output layer(s). Among other things this layer contains information about entities (e.g. debtors, protection providers…), commitments (e.g. credit facilities), instruments (e.g. loans, securities, deposits…) and protections (e.g. financial protection, physical protection like real estate protection) as well as aggregated information.

The Enriched Input Layer (EIL)

The Enriched Input Layer is another ERM and acts as an intermediate layer between the Input Layer and the Reference Output Layer. It represents the information of the input layer enriched by additional information (e.g. the result of particular derivations where the input parameters of the derivation may not be needed any more and are therefore not present in the Enriched Input Layer).

The Reference Output Layer (ROL)

The Reference Output Layer describes the Non-reference Output Layer using reference codes meaning the codes used in the Input Layer. The relationship between the Reference Output Layer and the Non-reference Output Layer is represented by Mappings (see Annex I: Non-technical introduction to SMCube methodology).

The Non-reference Output Layer (NROL)

The non-reference output layer describes the reporting requirements as defined in the related documents (e.g. regulations, directives, guidelines and manuals), sometimes using different codification systems (e.g. EBA ITS, SDMX…).

Please note that, although the output layer is part of the BIRD process, the actual definition of the output requirements (e.g. regulations) is out of scope of the BIRD. We rather translate the reporting requirements into the language of the BIRD, meaning that these reporting requirements are represented as cubes (e.g. FinRep EBA ITS that is described in the DPM / XBRL is (automatically) extracted and represented in the dictionary).


All phases may comprise validations, e.g. validations that ensure the integrity of the Input Layer, validations that ensure the consistency of the Enriched Input Layer, validations that apply (external) validation rules on the Non-reference Output Layer.

Phase 1 (IL -> EIL)

The first phase comprises the transformations that are applied on the Input Layer in order to generate the Enriched Input Layer. These transformations may be classified into the Preparation (of data) and the Enrichment (of data).

Phase 2 (EIL -> ROL)

This phase comprises the transformations that generate the Reference Output Layer based on the Enriched Input Layer. Additionally this phase may comprise technical adjustments necessary in order to comply with the Non-reference Output Layer.

Phase 3 (ROL -> NROL)

The third phase of the process comprises the application of Mappings describing the relationship between the Reference Output Layer and the Non-reference Output Layer.

Description of the datasets

The description of the datasets in the BIRD is provided following the SMCube methodology, which is a methodology developed with the objectives of:

  • Enabling the description within one dictionary of all types of datasets (registries, dynamic data for supervisory purposes, for monetary purposes…)
  • Facilitating the integration of dictionaries developed with different methodologies (like DPM/XBRL or SDMX) in one single dictionary by keeping a high degree of compatibility with the other methodologies

The version 1.0 of the SMCube methodology is finalised. The SMCube information model will be provided as soon as possible. A non-technical introduction to the main concepts of the methodology is provided in Annex I of this handbook.

The formal description of the BIRD datasets is provided in an Access database, which can be downloaded in the BIRD website.