Exploration of Possible Concept Models for Observables, Investigations, and Observation Results For the IHTSDO Observables Project Group Revision Date: March 11, 2013

Integrating situations, conditions, and observation results Adopt “situation” as the top level category, to include situation with explicit context and situation with implicit context i.e. finding. Split out non-situation findings – Observation results are not situations Remove “interprets” and “has interpretation” attributes from current SNOMED CT findings model – Increased, decreased, normal and abnormal are considered results, not targets of observation.

Situation: – A phase of life of the patient during which he/she is the bearer of a clinical condition Clinical condition: – A patient-related body process, disposition, or (patho-)anatomical structure, which is reportable in the context of health records.

Presence, absence Presence, absence are modeled as: “situation includes some condition” and “situation not includes some condition”

Observation result An information artifact – Is-about some observable – Has-value some {value}

Observation result model (1) – This model makes a distinction between the target of an observation – the thing the observation is about - such as an inherent quality or independent continuant that is being observed – and any aspects of the act of observation that defines the observation – Two parts of the observables model: – A) the quality/property part of the model: This models the thing being observed, which is the intended object of the observation – This part of the model deals with real entities that exist independent of being observed – B) the observation part of the model: This models the defining characteristics of the observation act – This part of the model deals with the various characteristics that define the type of observation that is done, such as technique, units, time scale, etc. These characteristics may also help us infer how we know, and how accurately we know, that the object of observation has the characteristics that are observed. The defining characteristics of the observation act are ontological with respect to acts of observation. Some people have called these “epistemological” and declared them out of bounds for an ontology, but this is a misunderstanding of what observables are about. These features are only out of bounds for an ontology of the targets of observation, but not out of bounds for “observables” as intended to be covered with this proposed model.

Observation result model (2) – uses a nested expression or pre-coordinated named dependent quality (or other type of entity) to represent what is being observed Note: there is a difference between “what is being observed” and “what the thing observed is a quality of” E.g. “color of skin”: What is being observed is color. The color happens to be a quality of skin, which might happen to have a particular location. – no role group is needed to define characteristics of the observation act, because we assume only one set of characteristics per act of observation – If the results of an observation are multiple, then the model requires that there be multiple individual observations. – observation result is a replacement for the name “finding” for those things that fit this model. – There is a closely correlated model for observation procedures: – observation procedures add the attribute: METHOD = observation action. – observation results add the attribute: HAS VALUE

Observation result model (3) What does this model do to existing measurement procedure attributes? – Replaces HAS SPECIMEN with DIRECT SITE – The DIRECT SITE is the immediate direct locus of the observation action (as opposed to the exact locus of the quality that is intended to be measured or assessed) and is to be used when the entity that is being directly observed is not at the same locus as the intended object of the observation. (The intended object of the observation is the entity in which the observed property inheres; or the independent continuant which is ideally intended to be observed). – Replaces MEASUREMENT METHOD with TECHNIQUE – Not all observations of interest are measurements, and “MEASUREMENT METHOD” is too close a name to “METHOD” which takes values from the action hierarchy to define procedures in SNOMED CT. – We will need to create a new value set for techniques – Revises and changes the configuration of COMPONENT, PROPERTY, SYSTEM – COMPONENT and SYSTEM – Replaced by INHERES-IN and TOWARDS. These are expected to achieve better reproducibility via clearer ontological definitions. – PROPERTY TYPE – Retains current properties and adds values related to PATO (ontology of qualities) – TIME ASPECT, and SCALE TYPE – Retains these attributes in the observation part of model, and add UNITS to coordinate with IFCC-IUPAC – Moves to their own hierarchies, separate from observables: functions processes activities – Allows functions, processes, activities also to be values of TOWARDS (in addition to substances, etc) – Does not allow observables to be values of INHERES-IN or TOWARDS.

Observation result model (4) – Differentiates between a dependent quality per se and a property type. – Concentration is a property type. – The concentration of sodium in serum is a dependent quality. – Renames PROPERTY to PROPERTY TYPE

Observation result model (5) – Deprecates the use of “absence” as a property type – Asserting absence of findings/functions/abilities/etc. requires negation (using a modification of the situation model). – Observables would also not use “associated morphology” But note: Conditions can be modeled using “associated morphology” with a value that implies physical absence of a structure that is normally present E.g congenital atresia, traumatic acquired absence – Deprecates the use of “presence” as a property type. – Presence is necessarily implied by conditions modeled with associated-morphology, but presence is not a property type for observables E.g supernumerary structure (morphologic abnormality) implies presence of an extra structure not normally present.

The observable part of the model Main attribute is: – IS ABOUT (observation target) Its domain includes observables, observation procedures, and observation results. Its range includes: – dependent qualities of independent continuants – properties of processes (aka “process profiles” in BFO2) Range MAY include: – Independent continuants » What does it mean for an observation to be modeled as “IS ABOUT” X, where X is independent? » What allowable values? present, absent, detected, not detected?

The observation part of the model Main attributes are: – TIME ASPECT – SCALE TYPE – UNITS – TECHNIQUE – DIRECT SITE

observable TIME ASPECT SCALE Time aspects Scale types DRAFT model for observables UNITS units TECHNIQUE techniques DIRECT SITE Body structures, specimens IS ABOUT Dep. Qualities/Dispositions, Indep. continuants

quality PROPERTY TYPE Property types DRAFT model for dependent qualities independent continuants INHERES IN TOWARDS Functions, substances PRECONDITION Body states

observable PROPERTY TYPE Property types TIME ASPECT SCALE Time aspects Scale types DRAFT model for ‘quality’ observables independent continuants INHERES IN TOWARDS Functions, substances UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states (challenges, fasting etc.) DIRECT SITE Body structures, specimens quality

observable PROPERTY TYPE Property types TIME ASPECT SCALE Time aspects Scale types DRAFT model for ‘quality’ observables independent continuants INHERES IN TOWARDS Functions, substances UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens IFCC-IUPAC NPU elementsLOINC elements Kind-of-propertyproperty System/specimensystem component Time aspect scale units method System/specimen component quality

observable PROPERTY TYPE Substance concentration TIME ASPECT SCALE Point in time quantitative LOINC Example: Sodium:SCnc:PT:Ser/Plas:Qn plasma INHERES IN TOWARDS Sodium ion UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Serum/plasma specimen quality Kind-of-property component Time aspect scale System/specimen

observable PROPERTY TYPE Substance concentration TIME ASPECT SCALE point in time quantitative IFCC-IUPAC NPU Example: P—Sodium ion; subst.c. = ? mmol/l plasma INHERES IN TOWARDS Sodium ion UNITS mmol/l TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens quality property system component units

Observation results TIME ASPECT SCALE Time aspects Scale types DRAFT model for observation results UNITS units TECHNIQUE techniques DIRECT SITE Body structures, specimens IS ABOUT qualities, dispositions, independent continuants HAS VALUE Numeric, ordinal, nominal

Observation result PROPERTY TYPE Property types TIME ASPECT SCALE Time aspects Scale types DRAFT model for results of observations of qualities independent continuants INHERES IN TOWARDS Functions, substances UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens quality VALUE Numeric, ordinal, nominal

Observation procedure PROPERTY TYPE Property types TIME ASPECT SCALE Time aspects Scale types DRAFT model for procedures that observe qualities independent continuants INHERES IN TOWARDS Functions, substances UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens quality METHOD Observation action

Attributes that define the quality that the observation is intended to elucidate – Property type Coordinated with BFO Qualities. Quality: a dependent continuant that is exhibited if it inheres in an entity or entities at all. (See BFO Manual, definition of “Quality”) – Inheres-in Relationship between a quality (property) and the independent continuant on which it depends for its existence, in which it is manifest – Towards (? Object)(? Target)(? Of) Third element of a relational quality, (other than the quality, and the continuant in which it inheres) e.g. sodium, in the quality of concentration of sodium in serum – Precondition States of the individual that contextualize the property (e.g. standing, fasting, post- challenge, etc)

Values for PROPERTY TYPE Detail Dimension Feature Fluid property Force property Location Quantity Ratio Result Stage Temperature Time Velocity Wave property Top levels of value hierarchy – determined by empirical analysis of values in the observables hierarchy

observable entity property types – dimension [2] (possible: size) area [20] distance (synonym: linear dimension) – breadth [20] – circumference [27] – depth [7] – diameter [31] – height [29] – length [42] – width [11]

Approach to properties Influenced by OBO Quality ontology

PRECONDITION – Body states that define the context in which the property is defined. For example, “standing blood pressure” is defined in the context of the body state “standing position”. Various challenge tests would be defined in terms of body states specifying the challenge that occurred, e.g. “2 hour post-prandial glucose” would have body state = “2 hours after meal”.

Attributes that define the characteristics of the observation – Time aspect Same as LOINC time aspect and current measurement procedure attribute – Scale type Same as LOINC scale type and current measurement procedure attribute – Units Same as IFCC-IUPAC NPU units – Direct site the direct object of the observation action; the site or specimen where the observation takes place. May be different from the value of INHERES- IN, since the property being observed may be inferred from a specimen or from a remote site. – Examples: rectum as the site of temperature measurement, where the property being observed is the core body temperature (rectal temperature being a surrogate); or serum specimen being used to determine body plasma sodium concentration. The concentration inheres in the plasma, but is being measured in a serum specimen. Needs to be modeled ONLY when this site is different from the value of INHERES-IN – Technique Any specialization of “observation” that tells us how we did the observing; for example, “enzyme-linked immunosorbent assay” or “immunofluorescence”.

SITE The attribute PROCEDURE SITE DIRECT could have its name changed to DIRECT SITE and could allow additional domains of observation result and observable – Could also revise PROCEDURE SITE to be SITE, and FINDING SITE to be SITE. – INHERES-IN can be a sub-role of SITE. This works for observation findings and observation procedures, and DIRECT SITE would be used in addition where necessary – Role hierarchy would look like this: SITE INHERES-IN DIRECT SITE (used for procedures, observation results, and observables) INDIRECT SITE (still used only for procedures)

Replace MEASUREMENT METHOD with more general TECHNIQUE Proposal: – For observation and evaluation procedures, the METHOD (with values from the action hierarchy) represents the goal or objective of what is done: evaluation, testing, imaging, measurement, examination – observation techniques define the observable, via TECHNIQUE (with values from a value set that includes lab techniques and other specific measurement and evaluation actions, such as inspection, palpation, percussion, auscultation) Techniques are the means by which the action is carried out, not the intended outcome. Techniques include specific measurement techniques such as Enzyme- linked immunosorbent assay (ELISA). – Need to examine whether this works for procedures other than evaluations, i.e. can we make the distinction between METHOD (means) and TECHNIQUE for all procedures

Observable PROPERTY TYPE Threshold TIME ASPECT SCALE Point in time quantitative Auditory threshold at 3kHz, in dB Auditory system INHERES IN TOWARDS Hearing (function) UNITS dB TECHNIQUE 3 kHz audiometry IS ABOUT PRECONDITION Body states DIRECT SITE ear quality

PRECONDITION Body states quality PROPERTY TYPE Mass concentration Blood hemoglobin concentration (quality) Intravascular blood INHERES IN TOWARDS hemoglobin

PRECONDITION observable PROPERTY TYPE Mass concentration TIME ASPECT SCALE Point in time quantitative Blood hemoglobin concentration, quantitative, single point in time (observable) Intravascular blood INHERES IN TOWARDS hemoglobin UNITS units TECHNIQUE techniques IS ABOUT Body states DIRECT SITE Body structures, specimens quality

PRECONDITION Observation result PROPERTY TYPE Mass concentration TIME ASPECT SCALE Point in time quantitative Blood hemoglobin 14 gm/dL (observation result) Intravascular blood INHERES IN TOWARDS hemoglobin UNITS gm/dL TECHNIQUE techniques IS ABOUT Body states DIRECT SITE Body structures, specimens quality VALUE 14

PRECONDITION Body states quality PROPERTY TYPE circumference Head circumference (quality) Head (necessarily also: surface along fronto-parietal coronal plane of head) INHERES IN TOWARDS hemoglobin

PRECONDITION Observation result PROPERTY TYPE circumference TIME ASPECT SCALE Point in time quantitative Head circumference in cm (observable) head INHERES IN TOWARDS hemoglobin UNITS cm TECHNIQUE techniques IS ABOUT Body states DIRECT SITE Body structures, specimens quality

PRECONDITION Observation result PROPERTY TYPE circumference TIME ASPECT SCALE Point in time quantitative Head circumference 42 cm (observation result) head INHERES IN TOWARDS hemoglobin UNITS cm TECHNIQUE techniques IS ABOUT Body states DIRECT SITE Body structures, specimens quality VALUE 42

PRECONDITION observable PROPERTY TYPE concentration TIME ASPECT SCALE Point in time quantitative Serum concentration of Borrelia antibody plasma INHERES IN TOWARDS Borrelia antibody UNITS units TECHNIQUE techniques IS ABOUT Body states DIRECT SITE Serum specimen quality

PRECONDITION Observation procedure PROPERTY TYPE concentration TIME ASPECT SCALE Point in time quantitative Measuremement of serum concentration of Borrelia antibody by ELISA technique plasma INHERES IN TOWARDS Borrelia antibody UNITS units TECHNIQUE ELISA IS ABOUT Body states DIRECT SITE Serum specimen quality METHOD Measurement action

PRECONDITION Observation result PROPERTY TYPE serogroup TIME ASPECT SCALE Time aspects scales Cultured E.coli serotype is O157 E. Coli (organism) INHERES IN TOWARDS hemoglobin UNITS units TECHNIQUE Bacterial serotyping IS ABOUT Body states DIRECT SITE Microbial culture quality VALUE O157 The information model is used to link this result to the Culture and specimen that came from the patient.

What about abilities? Able with respect to normal functioning and activities – Ontologically these are “realizables”. – Two types: Sure-fire (“dispositions”): if you have the ability to feel pain, then when a painful stimulus is applied, you feel it (assuming you are conscious – and actually even if you are unconscious – with some exceptions based on threshold of intensity) Those abilities that depend on the bearer’s decision (ability to walk, talk, throw a ball, eat an apple, etc)

Disposition type Possible replacement for “property type” where the value of “IS ABOUT” is neither a quality nor a process, but instead is a disposition or function – * could consider expanding the domain/range for PROPERTY TYPE instead

disposition DISPOSITION TYPE ability ability to hear (meaning the “sure-fire” disposition for a hearing process to be instantiated on exposure to sound) auditory system INHERES IN TOWARDS hearing (process) PRECONDITION Body states

PRECONDITION Body states Observation result DISPOSITION TYPE ability TIME ASPECT SCALE Time aspects Scale types Able to hear (as an observation result) (there exists some observation result which has a target of some disposition which is ability to hear) auditory system INHERES IN TOWARDS hearing (process) UNITS units TECHNIQUE techniques IS ABOUT DIRECT SITE Body structures, specimens disposition VALUE able

PRECONDITION Body states situation DISPOSITION TYPE ability Able to hear (as disposition included in situation, or “ability to hear = present”) (the situation includes the existence of some disposition which is ability to hear) auditory system INHERES IN TOWARDS hearing (process) INCLUDES disposition

PRECONDITION Body states Observation result DISPOSITION TYPE ability TIME ASPECT SCALE Time aspects Scale types Able to hear (as an observation result, using the VALUE attribute) auditory system INHERES IN TOWARDS hearing (process) UNITS units TECHNIQUE techniques IS ABOUT DIRECT SITE Body structures, specimens disposition VALUE able

Observation result DISPOSITION TYPE Ability TIME ASPECT SCALE Time aspects Scale types VALUE able Auditory system INHERES IN TOWARDS hearing (process) UNITS units TECHNIQUE techniques PRECONDITION Body states DIRECT SITE Body structures, specimens able to hear (as a situation that includes an observation result, with an obs-target) situation INCLUDES IS ABOUT disposition

DISPOSITION TYPE Impaired ability Impaired ability to hear (as a disposition) auditory system INHERES IN TOWARDS hearing (process) PRECONDITION Body states

PRECONDITION Body states Observation result DISPOSITION TYPE ability TIME ASPECT SCALE Time aspects Scale types Impaired ability to hear (as an observation result) auditory system INHERES IN TOWARDS hearing (process) UNITS units TECHNIQUE techniques IS ABOUT DIRECT SITE Body structures, specimens disposition VALUE impaired

PRECONDITION Body states situation DISPOSITION TYPE Impaired ability Impaired ability to hear (as disposition included in situation, or “impaired hearing = present”) auditory system INHERES IN TOWARDS hearing (process) INCLUDES disposition

Other dispositions Antimicrobial sensitivity

Observation procedure DISPOSITION TYPE Resistance/sensitivity TIME ASPECT SCALE Time aspects Scale types Antimicrobial susceptibility test Microbial isolate INHERES IN TOWARDS Antimicrobial UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens disposition METHOD Observation action

observable PROPERTY TYPE Briskness of response TIME ASPECT SCALE Time aspects Scale types Left knee deep tendon reflex - briskness INHERES IN TOWARDS Deep tendon reflex UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens quality Neuromuscular structures of the left knee deep tendon reflex

Observation result PROPERTY TYPE Briskness of response TIME ASPECT SCALE Time aspects Scale types Left knee jerk reflex 2+ INHERES IN TOWARDS Deep tendon reflex UNITS units TECHNIQUE techniques IS ABOUT PRECONDITION Body states DIRECT SITE Body structures, specimens quality Neuromuscular structures of the left knee deep tendon reflex VALUE 2+ out of 4+

quality PROPERTY TYPE Histologic type Histologic type (of lesion) lesion INHERES IN TOWARDS Functions, substances PRECONDITION Body states

quality PROPERTY TYPE Located in Tumor site (located-in would be a relational spatial quality) tumor INHERES IN TOWARDS Functions, substances PRECONDITION Body states

Dealing with “presence” Disallow “presence” and “absence” as a value of PROPERTY TYPE But allow “detected”, “present”, “absent” as an observation result, if the “IS ABOUT” is an independent continuant (not a dependent continuant).

VALUE Detected Methicillin-resistant staphylococcus aureus (MRSA) present in abdominal wound, swab specimen, by PCR rapid detection method (A) Observation result TIME ASPECT SCALE Single point in time qualitative UNITS units TECHNIQUE PCR rapid detection method DIRECT SITE Abdominal wound swab (specimen) MRSA (organism) IS ABOUT HAS LOCATION Abd. wound

VALUE detected Mycoplasma pneumoniae detected Observation result TIME ASPECT SCALE Single point in time qualitative UNITS units TECHNIQUE techniques DIRECT SITE specimens Mycoplasma pneumoniae IS ABOUT

Observation result TIME ASPECT SCALE Single point in time qualitative Methicillin-resistant staphylococcus aureus (MRSA) present in abdominal wound, swab specimen, by PCR rapid detection method (B - situation) UNITS units TECHNIQUE PCR rapid detection method DIRECT SITE Wound swab (specimen) MRSA (organism) IS ABOUT HAS LOCATION Abd. wound situation INCLUDES

Observation result TIME ASPECT SCALE Single point in time qualitative Methicillin-resistant staphylococcus aureus (MRSA) present in abdominal wound, swab specimen, by PCR rapid detection method (B - situation) UNITS units TECHNIQUE PCR rapid detection method DIRECT SITE Wound swab (specimen) MRSA (organism) IS ABOUT HAS LOCATION Abd. wound situation INCLUDES VALUE present

observation procedure IS ABOUT MRSA (organism) TIME ASPECT SCALE Time aspects Scale types VALUE Numeric, ordinal, nominal MRSA (methicillin resistant staph aureus) POC (point-of-care) test (procedure) UNITS units TECHNIQUE MRSA POC detection technique DIRECT SITE specimen METHOD Observation action

observable TIME ASPECT SCALE Time aspects Scale types UNITS units TECHNIQUE palpation DIRECT SITE Ventral aspect of wrist over radial artery Radial pulse palpability Arterial pulsation IS ABOUT HAS LOCATION Radial artery at the wrist

Observation result TIME ASPECT SCALE Time aspects Scale types VALUE present UNITS units TECHNIQUE palpation DIRECT SITE Ventral aspect of wrist over radial artery Radial pulse present by palpation (1) Arterial pulsation IS ABOUT HAS LOCATION Radial artery at the wrist

Observation result TIME ASPECT SCALE Time aspects Scale types UNITS units TECHNIQUE palpation DIRECT SITE Ventral aspect of wrist over radial artery Radial pulse present by palpation (2) Arterial pulsation IS ABOUT HAS LOCATION Radial artery at the wrist situation INCLUDES

Observation result TIME ASPECT SCALE Time aspects Scale types VALUE present UNITS units TECHNIQUE techniques DIRECT SITE place Abdominal wall stoma present (A) stoma IS ABOUT HAS LOCATION Abdominal wall

Observation result TIME ASPECT SCALE Time aspects Scale types VALUE present UNITS units TECHNIQUE techniques DIRECT SITE place Colostomy present (A) colostomy IS ABOUT HAS LOCATION Abdominal wall

Observation result TIME ASPECT SCALE Time aspects Scale types VALUE present UNITS units TECHNIQUE techniques DIRECT SITE place Adenocarcinoma of the colon present (A) adenocarcinoma IS ABOUT HAS LOCATION colon

Observation result TIME ASPECT SCALE Time aspects Scale types UNITS units TECHNIQUE techniques DIRECT SITE place Adenocarcinoma of the colon present (B1) adenocarcinoma IS ABOUT HAS LOCATION colon situation INCLUDES

Adenocarcinoma of the colon present (B2) adenocarcinoma HAS LOCATION colon situation INCLUDES

Determining “contents” Observations that seek to answer: – What things are present as physical parts of a specimen (such as a fluid) or structure? – What things are present and contained within a structure (but not part of it)?

observable PROPERTY TYPE Having physical part TIME ASPECT SCALE Time aspects Scale types Contents of urine by light microscopy (observable) urine INHERES IN TOWARDS Functions, substances UNITS units TECHNIQUE Light microscopy PRECONDITION Body states DIRECT SITE Body structures, specimens Assumes “having physical part” is a valid relation between discrete solid entities in a fluid and the fluid substance. IS ABOUT quality

observation procedure PROPERTY TYPE Having physical part TIME ASPECT SCALE Time aspects Scale types Determining contents of urine by light microscopy on urine sample (procedure) Synonym: microscopic urinalysis urine INHERES IN TOWARDS Functions, substances UNITS units TECHNIQUE Light microscopy PRECONDITION Body states DIRECT SITE Urine sample METHOD Observation action IS ABOUT quality

PROPERTY TYPE Having physical part TIME ASPECT SCALE Time aspects Scale types VALUE Observed Urine microscopy: hyaline casts present urine INHERES IN TOWARDS Hyaline casts UNITS units TECHNIQUE Light microscopy PRECONDITION Body states DIRECT SITE Urine specimen Observation result IS ABOUT quality

What about counts? Count >=1 means the same as present How should this be handled?

PROPERTY TYPE entitic number TIME ASPECT SCALE Time aspects quantitative VALUE 4 4 retinal hemorrhages present (a) retina INHERES IN TOWARDS hemorrhages UNITS units TECHNIQUE techniques PRECONDITION Body states DIRECT SITE Body structures, specimens Observation result IS ABOUT quality

Observation result PROPERTY TYPE entitic number TIME ASPECT SCALE Time aspects quantitative VALUE 4 4 retinal hemorrhages present (b) retina INHERES IN TOWARDS hemorrhages UNITS units TECHNIQUE techniques PRECONDITION Body states DIRECT SITE Body structures, specimens situation INCLUDES IS ABOUT quality

Observation result PROPERTY TYPE entitic number TIME ASPECT SCALE Time aspects quantitative VALUE >= 1 retinal hemorrhage present (A) retina INHERES IN TOWARDS hemorrhage UNITS units TECHNIQUE techniques PRECONDITION Body states DIRECT SITE Body structures, specimens IS ABOUT quality

Observation result TIME ASPECT SCALE Time aspects qualitative Retinal hemorrhage present (B) UNITS units TECHNIQUE techniques DIRECT SITE sites hemorrhage IS ABOUT HAS LOCATION retina situation INCLUDES

Retinal hemorrhage present (C) hemorrhage HAS LOCATION retina situation INCLUDES

Which models are preferred and why? Several different options have been presented Criteria for choosing among options: – 1) semantic consistency – 2) simplicity – 3) interoperability – 4) reproducibility of modeling individual concepts – 5) lower degree of disruption of existing implementations and content – 6) lower comparative cost of the change – 7) computability