PMML 2.1 -- PMML Conformance

PMML Document Validity

PMML is a standard for XML documents which express trained instances of analytic models. The following classes of model are addressed:

• Association Rules
• Decision Trees
• Center-Based & Distribution-Based Clustering
• Regression
• General Regression
• Neural Networks
• Naive Bayes
• Sequences

A valid PMML 2.1 document must be an XML document that is valid with respect to the reference XML Schema found at https://www.dmg.org/v2-1/PMML-2-1.xsd, after removing additional attributes that have a name with the prefix "x-". Additional elements with a name prefix "X-" can be defined in an internal Schema. A valid PMML 2.1 document must obey the restrictions expressed in the model specifications found at https://www.dmg.org/v2-1/GeneralStructure.html.

The model specifications define various restrictions which are not implemented in the XML Schema. Examples are:

"The value of %FIELD-NAME; must refer to a field in the data dictionary or in the transformation dictionary."

or

"There must be no more than two interval elements in a DataField"

PMML Conformance

PMML intends to enable application portability, sharing, and reuse of analytic models produced by a variety of tools. Conformance must therefore be specified from both producer and consumer perspectives. Applications need ways to specify what kinds of analytic models they can use, and modeling tools need ways to specify what kinds of analytic models they produce. A PMML document is what gets produced by a modeling tool to specify a trained analytic model and is what an application uses to deploy that model. Satisfying producer conformance rules ensures a model definition document is syntactically correct and in fact defines a model instance which is consistent with semantic criteria that are defined in model specifications. Satisfying consumer conformance rules ensures that such a model will be applied in ways which are valid.

Producer Conformance

A tool or application is producer conformant if it generates valid PMML documents for at least one type of model; a producer conformance statement must include which types of models are supported in this way. Producer conformance is a "contract" between a data mining tool/application vendor and users and application suppliers which states that the PMML documents defining models of those types it supplies can be integrated and used.

Consumer Conformance

An application is consumer conformant if it will accept valid PMML documents for at least one type of model. A consumer conformance statement must indicate which types of models are accepted. Application conformance is a "contract" between the application suppliers and both users and data mining tool/application vendors which states that PMML documents defining models of those types can be integrated and used. An essential example is that if an application is consumer conformant for Polynomial-Regression-model types, then valid PMML documents defining models of this type produced by different producers would be interchangeable in the application.

Core and Non-Core Features

For a given class of model, the corresponding XML Schema and specifications identify core features which all conforming producers and consumers must support and non-core features which may optionally be supported.