International Paralympic Committee position stand—background and scientific principles of classification in Paralympic sport
Authors: Tweedy S M , Vanlandewijck Y C 
Published: October 2009

The Classification Code of the International Paralympic Committee (IPC), inter alia, mandates the development of evidence-based systems of classification. This paper provides a scientific background for classification in Paralympic sport, defines evidence-based classification and provides guidelines for how evidence-based classification may be achieved.Classificationis a process in which a single group of entities (or units) are ordered into a number of smaller groups (or classes) based on observable properties that they have in common, andtaxonomyis the science of how to classify. Paralympic classification is interrelated with systems of classification used in two fields:▶Health and functioning. TheInternational Classification of Functioning, Disability and Healthis the most widely used classification in the field of functioning and health. To enhance communication, Paralympic systems of classification should use language and concepts that are consistent with theInternational Classification of Functioning, Disability and Health.▶Sport. Classification in sport reduces the likelihood of one-sided competition and in this way promotes participation. Two types of classification are used in sport—performance classification and selective classification. Paralympic sports require selective classification systems so that athletes who enhance their competitive performance through effective training will not be moved to a class with athletes who have less activity limitation, as they would in a performance classification system.Classification has a significant impact on which athletes are successful in Paralympic sport, but unfortunately issues relating to the weighting and aggregation of measures used in classification pose significant threats to the validity of current systems of classification.To improve the validity of Paralympic classification, the IPC Classification Code mandates the development of evidence-based systems of classification, an evidence-based system being one in which the purpose of the system is stated unambiguously; and empirical evidence indicates the methods used for assigning class will achieve the stated purpose. To date, one of the most significant barriers to the development of evidence-based systems of classification has been absence of an unambiguous statement of purpose. To remedy this, all Paralympic systems of classification should indicate that the purpose of the system is to promote participation in sport by people with disabilities byminimising the impact of eligible impairment types on the outcome of competition. Conceptually, in order to minimise the impact of impairment on the outcome of competition, each classification system should:▶describe eligibility criteria in terms of:⊳type of impairment and⊳severity of impairment;▶describe methods for classifying eligible impairments according to the extent of activity limitation they cause.To classify impairments according to the extent of activity limitation they cause requires research that develops objective, reliable measures of both impairment and activity limitation and investigates the relative strength of association between these constructs in a large, racially representative sample. The paper outlines a number of objective principles that should considered when deciding how many classes a given sport should have: the number of classes in a sport should not be driven by the number of athletes in a sport at a single time point.