Table 3. NIHR-RD-TRC assessment scale.

Stage	Description	Example
Foundation	The basis of characterizing the disease in HPO needs to be developed	HPO is good for describing dysmorphologies especially across species: how do you model and use dyslexia?
Formulation	The theory is defined but key details need to be defined and handled in the ontology computations	HPO models biology, where diseases are caused by environmental factors, e.g. cancers — how can an environment ontology be included?
Refinement	The key data sets and definitions for the disease are identified and available but require ‘translation’	Theme based registry systems hold collections of data in other coding systems (registry-specific or ICD) — how can these be mapped onto HPO?
Maturity	The HPO framework is in place and productive results are being obtained, the HPO term set continues to evolve	The HPO basics are in place and a set of Phenotypes in place — do we need more terms or do existing terms need modification?