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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>CAOS</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>An Exploration into Cognitive Bias in Ontologies</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>C. Maria Keet</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University of Cape Town</institution>
          ,
          <addr-line>18 University Avenue, Rondebosch, Cape Town 7701</addr-line>
          ,
          <country country="ZA">South Africa</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2021</year>
      </pub-date>
      <volume>5</volume>
      <fpage>11</fpage>
      <lpage>18</lpage>
      <abstract>
        <p>Ontologies and similar artefacts are used in a myriad of ontology-driven information systems and increasingly also linked to data analytics. Algorithmic bias in data analytics is a well-known notion, but what does bias mean in the context of ontologies that provide a structuring mechanism for, e.g., an algorithm's or query's input? What are the sources of bias there, and cognitive bias in particular, and how do they manifest in ontologies? We examined and enumerated eight broad sources that can cause bias that may afect an ontology's content. They are illustrated with examples from extant ontologies and samples from the literature. We then assessed three concurrently developed COVID-19 ontologies on modelling bias and detected diferent subsets of types of bias in each one, to a greater or lesser extent. This first characterisation aims contribute to a sensitisation of bias in ontologies primarily regarding representation of the knowledge.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Ontology development</kwd>
        <kwd>Cognitive bias</kwd>
        <kwd>Modeling</kwd>
        <kwd>AI Ethics</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Bias in IT systems is a popular topic in the media and recent special tracks at conferences.
Nearly all reports on bias in ‘models’ concern statistical or neural models created from some Big
Data dataset by means of knowledge discovery, machine learning, and deep learning techniques.
There are many more types of models, however, notably ontologies and knowledge graphs,
whose success stories include, among others, the Gene Ontology [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] and representation language
standards such as OWL [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], and the repository of ontology repositories OntoHub has indexed
22460 ontologies gathered from of 139 repositories1. Ontologies for information systems provide
an application-independent representation of the subject domain. Besides their use in data
integration, one also can choose an ontology upfront and use it in a stand-alone application or
on the Web, such as Google’s Knowledge Graph that drives the creation and maintenance of its
infoboxes [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. The person who builds and controls the ontology or knowledge graph, then, is
the one who has the power to control presentation and access to information and possibly also
the recording of information. In the case of Google’s Graph, Vang argues it “to some degree
contests the autonomy of the user” [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>
        It is not inconceivable that ontologies also may be biased, which would then propagate into
the information systems. A recurring theme is “encoding bias” [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], which refers to merely
diferent formalisations of the same thing. There is, however, scant literature about cognitive
bias in ontologies, with, to the best of our knowledge, three preliminary papers only [
        <xref ref-type="bibr" rid="ref6 ref7 ref8">6, 7, 8</xref>
        ].
Gomes and Bragato Barros [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] assessed bias in the Friend of a Friend (FOAF) terminology
through the lens of discursive semiotics as a method, which was limited to a few well-known
issues, being first &amp; last name (vs given &amp; family), gender, and the meaning of document. Biases
are more intricate and varied than these. For instance, and what Gomes’ approach cannot
capture, is, among others, the menopausal hormone therapy case2: there were at least economic
incentives that determined which properties were represented in the medical ontology with what
threshold values in order to classify who was eligible for treatment. An example in conceptual
data modelling concerns the “Dirty War Index” tool that aimed to inform public health policy in
armed conflict settings, where a politically motivated bias of illusory superiority was observed
that afected the tool’s outcome due to varying levels of granularity in the model in favour of the
authors’ side in the conflict [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. For software and ontology development, research into cognitive
bias is focussed on the biases in development processes [
        <xref ref-type="bibr" rid="ref10 ref9">9, 10</xref>
        ] rather than the resultant models,
with aforementioned exceptions of the FOAF [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] and a few anecdotes [
        <xref ref-type="bibr" rid="ref7 ref8">7, 8</xref>
        ]. We are interested in
an ontology’s content first, i.e., possible efects of a bias, before investigation the development
processes that may have caused it: if no outcomes can be detected, then one would not have to
undertake the more costly investigation into processes.
      </p>
      <p>
        In this paper, we aim to contribute to systematising the sort of bias that may be present in
ontologies, including similar artefacts such as conceptual data models and thesauri, which may
help their management and prevention. In addition to extending Gomes and Bragato Barros’
three sources [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] to eight, we seek to provide a preliminary answer to what bias means for
ontologies, what their sources are, and how that manifests itself in ontologies, and therewith go
beyond the anecdotes in [
        <xref ref-type="bibr" rid="ref6 ref7 ref8">6, 7, 8</xref>
        ]. The identified broad categories for biases are structured along
three categories: high-level philosophical ones, scope or purpose, and subject domain issues.
Some of them are intentional biases that insiders know very well, but outsiders and newcomers
need to become aware of. Second, we assess three COVID-19 ontologies on these biases. These
ontologies are under active development and relevant for data and information management of
the pandemic. The assessment showed that none is free of bias and contain diferent subsets of
cognitive and other biases rather than explicitly competing as the better alternative.
      </p>
      <p>The remainder of this paper is structured as follows. We systematise and illustrate the
principal sources (Sect. 2) first and then assess the COVID-19 ontologies (Sect. 3). We discuss
the outcomes and touch upon automated reasoning (Sect. 4) and close with conclusions (Sect. 5).</p>
      <p>2In short: the range of natural variability of concentrations of key molecules was narrowed down to increase
the number of ‘abnormal’ women that then qualified for medication, which unintentionally led to an increase in
cancer incidence. An accessible account of the complicated story can be found at: https://www.cancer.org/cancer/
cancer-causes/medical-treatments/menopausal-hormone-replacement-therapy-and-cancer-risk.html.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Principal Sources of Bias in Ontologies</title>
      <p>
        Since the notion of bias in ontologies is unclear beyond a few recorded anecdotes for knowledge
graphs [
        <xref ref-type="bibr" rid="ref6 ref7">6, 7</xref>
        ], the net was cast wider to also consult various lists and taxonomies of biases,
notably [
        <xref ref-type="bibr" rid="ref11 ref12">11, 12</xref>
        ], and it also required availing of the author’s experience in ontology development
(among others, [
        <xref ref-type="bibr" rid="ref13 ref14">13, 14</xref>
        ]), their assessments over the years in an educational setting including
for the textbook [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ], and inspection for use, reuse, and reviewing and so on. Therefore, we
commence with a few preliminary considerations on the cognitive biases lists, to then proceed
to a description of each of the identified bias sources for ontologies.
      </p>
      <sec id="sec-2-1">
        <title>2.1. Preliminary Considerations</title>
        <p>
          Of most consequences are the cognitive biases in task and domain ontologies, since they are
expected to be used most often in information systems. There may be a knock-on efect from
philosophical and engineering (encoding) dimensions, so that has to be considered as well. Also,
an inclusive definition for bias is adopted, as in [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ], where it is a consequence of interference
with honest attempts, rather than only the narrow scope of norm deviation and error3.
        </p>
        <p>
          The notion of bias has been interpreted in a varied manner, from clear short lists of cognitive
biases to also include cognitive styles and alternate perspectives and image schemas. Cognitive
biases in the literature for IT and computing more specifically, are grouped according to one’s
dimension of interest; e.g., by type of task (estimation, decision, recall, etc.) for information
visualisation [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ], by software engineering “knowledge area” (e.g., design, testing, management)
[
          <xref ref-type="bibr" rid="ref9">9</xref>
          ] and as cognitive styles in the approach to ontology development [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ]. Dimara et al’s most
recent and comprehensive list contains 154 cognitive biases [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ]. Many of them are not relevant
within the scope of ontologies, just like only a subset was relevant to them for information
visualisation [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ]. For instance, while the ‘Verbatim efect’—it is easier to recall the gist of
something than the sentence(s)—is indeed a bias, it does not afect the content of an ontology,
and a ‘Ballot names bias’ on a voting sheet is completely irrelevant. Also, a large subset of
that inventarisation have to do with processes, which may be relevant for assessing ontology
development methodologies and practices. The borderline between processes and the content
may be unclear and dificult to establish for individual ontologies when one has not been privy
to the development process. For instance, the ‘Mere-exposure efect’ cognitive bias might
be observed when choosing to reuse a particular ontology because of its familiarity more so
than based on critical evaluation of the ontologies, and an outsider would not know when the
rationale remains undocumented.
        </p>
        <p>A second note of consideration is whether a bias may be implicit or explicit. Here, we take
‘explicit’ to mean a conscious decision for one thing or another to appear as such in the ontology.
For instance, a choice for developing a realism-based ontology, or explicitly representing that
Tomato ⊑ Fruit, since it is so according to science and the classification criteria of biologists.
Other choices may be ‘implicit’, in the sense of not having realised it at the time of modelling.</p>
        <p>3An ontological analysis of cognitive bias may be of use, since definitions of bias difer across the scientific and
popular literature, to go to being as inclusive as bias being an image schema or viewpoint that is diferent from one’s
own. Also, the notion of ‘norm deviation’ may already be dificult to operationalise for an ontology that claims to
be ‘universal’, since norms vary widely across the globe.
Subject domain</p>
        <p>Subtype
Science
Granularity
Linguistic
Socio-cultural
Political or religious
Economics
They may, or may not, be, unintended in hindsight, but at least it was not a deliberate choice
among alternatives considered at development time.</p>
        <p>We categorise the biases by broad sources of a domain, in style with the focus on an ontology’s
content. We identified eight broad sources, which are summarised in Table 1. They will be
elaborated on in the next section. They are, at present and for the purpose and limited length of
this paper, high-level groupings that afect the representation of knowledge in the ontologies.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. High-level Philosophical Viewpoints</title>
        <p>Ontologies are an engineering version of the original idea of Ontology by philosophers. Most
subject domain ontology developers may not be interested in the finer distinctions of core
notions, but they are there. Practically, for domain ontology development, one may choose a
particular foundational ontology that provides the main types of entities and relations so as to
help structuring the content. There are multiple top-level and foundational ontologies, such as
BFO [16], DOLCE [17], and YAMATO [18], which contain diferent commitments. Its developers
are mostly clear about general principles and how it afects the ontology’s content, such as
whether it is descriptive or realist. This has a consequent efect on the ontology’s content,
such as admitting the existence of abstract entities or not [17], and what the core relations in
the world would be [19]; comprehensive comparisons can be found in [20, 21]. Choosing a
foundational ontology is a deliberate decision; hence, an explicit bias.</p>
        <p>There are related debates about whether an ontology’s contents is a representation of reality
or our understanding thereof, or whether there would even be a reality. This is a recurring
debate (see, e.g., [22]) that has no resolve that everyone agrees on. For ontology development,
the key issue to determine is whether one aims to be faithful to reality (or our best understanding
of it) versus ulterior motives, be it rejecting reality or not caring (‘post-truth’) or knowingly
violating it for some reason. These diferent stances have their main efects at the subject
domain level where the bias can have most efect, as we shall see below, and could result either
in an explicit or an implicit bias.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. Purpose with Encoding Bias</title>
        <p>
          In theory and historically, ontologies are supposed to be application-independent, so as to be
a solution to the data integration problem. If they are tailored to the application nonetheless,
they may become part of the problem. This application independence may not always hold.
Developing an ontology for the sake of it may be an interesting endeavour, but someone has to
fund it and it helps to have a use case to motivate for its development. This may afect what is
represented and how and is an explicit bias motivated by pragmatics. Uschold and Gruninger
call this “encoding bias” [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ], which are engineering choices rather than a cognitive bias and
they may give rise to “modelling styles” when several recurring choices are taken together [23].
This is normally not considered as a bias in AI ethics and bias research in cognitive science.
We illustrate it nonetheless, because it afects the actual representation of knowledge in the
ontology and, upon closer inspection, may induce arguments about the ontological nature of
things. Consider the following three characteristic approaches for diferent scenarios for the
same knowledge, to represent that ventilation is a treatment for COVID-19 patients:
A. If the aim is to be as detailed and reusable as possible, Treatment can be a type of
perdurant (colloquially: a type of process) within the common 3-dimensionalism viewpoint
(objects persist in time) and then Ventilation ⊑ Treatment is the bare minimum to
declare. Availing of the core participation relation between objects and processes, then also
Patient ⊑ ∃participatesIn.Treatment. One then may assert that our hospitalised COVID-19
patients participate in the ventilation treatment.
        </p>
        <p>B. A compact representation results in faster data processing, such as for ontology-based data
access. For instance, Patient ⊑ ∃isOnVentilator.Boolean, where one uses the ontology
language to develop a conceptual data model for databases, rather than the traditional
Extended Entity-Relationship language. This is a diferent ontological commitment from
option 1, because the ventilation treatment is now a property of a person, not a relational
property between two entities.</p>
        <p>C. If the aim is, e.g., annotation of literature to better manage it, then neither the boolean nor
all those constraints and relations are needed. Instead, one casts the net wide regarding
terminology by specifying preferred and alternative labels, including the alternately used
(but not equivalent) terms ventilator support, ventilation therapy, mechanical ventilation, and
invasive ventilation that have Broader Term (BT) Ventilation and Related Term (RT) Patient.
The ontologist may complain about the latter two options as woefully underspecified or too
imprecise, whereas the tool developers of options 2 and 3 may complain that the first option is
too complicated due to their preference for scalability or simplicity.</p>
      </sec>
      <sec id="sec-2-4">
        <title>2.4. Subject Domain</title>
        <p>
          The list of bias sources described in this section overlaps with Gomes and Bragato Barros’ one
[
          <xref ref-type="bibr" rid="ref6">6</xref>
          ], but is extended with three categories, including one from [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]. In addition, we indicate
whether they concern mainly explicit or implicit biases, or both, and illustrate each one in order
to demonstrate relevance.
        </p>
        <sec id="sec-2-4-1">
          <title>2.4.1. Diference of Opinion on Reality and Science</title>
          <p>Even under the assumption of a commitment to the existence of reality, one still could disagree.
A common example is whether a virus is an organism or not; it is not by any extant definition
of what an organism is. Bio-ontologies and medical terminologies do not agree on this matter,
such as the CIDO [24] versus the SIO [25] ontologies. More broadly, it concerns either the
insuficient insight or competing theories that the scientists still have to investigate, or there are
delays in propagating discoveries into the ontologies. It is assumed that eventually there will be
an agreement. In other areas, there are inherently competing theories, such as capitalism and
socialism, that would result in a diferent domain ontology of economy. They are all intended
choices and, arguably, just diferent image schemas or perspectives, or indeed biases.</p>
        </sec>
        <sec id="sec-2-4-2">
          <title>2.4.2. Required or Chosen Level of Precision/Granularity</title>
          <p>It is a general question in ontology development how detailed it should be and how deep the
taxonomy should go. Less detail therefore may be an act of omission, an indication of not needed,
which both may be results of a cognitive bias, or be merely a ran out of time situation for it to be
included in a next release. Inspecting an ontology in isolation, this is impossible to determine
unless it is explicitly stated in the annotations or accompanying documentation. For instance,
The Gene Ontology has three versions: a GO basic that excludes several relations between
entities, the GO, and a GO plus with additional axioms4.</p>
          <p>
            An act of omission is aggregating ex-military persons with non-involved persons as one
group of Civilians, which happened with aforementioned Dirty War Index tool even though the
original source had a more detailed categorisation [
            <xref ref-type="bibr" rid="ref8">8</xref>
            ]. Similar issues exist for other conflict
databases, which may be intentional or unintentional. For instance, a bombing may be recorded
as an instance of having targeted a Government building if that is the only class available, or more
precisely only if it had a hierarchy of subclasses, such as Health facility with subclasses including
State hospital and State medicine manufacture plant and a Defence facility class with, say, Military
base and Homeland security torture bunker as subclasses, rather than one layer of subclasses as
in [26]. Such diferentiations, or absence thereof, may be intended or they may be unintended.
          </p>
        </sec>
        <sec id="sec-2-4-3">
          <title>2.4.3. Cultural-linguistic Motivations</title>
          <p>
            Anyone who has learned a second language has come across untranslatable words or at least
ifne semantic distinctions. The question then arises if, and if so, when, a diference is a bias in
the ontology or not. For instance, English has only one term for river—all rivers are just rivers—
whereas French makes a distinction between a fleuve and a rivière—one flows into another river,
the other flows into the sea—that somehow has to be represented and the ontologies aligned
[27]. It is likewise for observed diferences in part-whole relations across languages [
            <xref ref-type="bibr" rid="ref14">14</xref>
            ]. One
may argue that in both examples, the reality is the same but they have varying descriptions,
or that there are diferent conceptualisations, or use the term reality more liberally and state
that there are diferent realities depending on language. This is, at the core, an explicit choice
between philosophical viewpoints.
          </p>
          <p>4http://geneontology.org/docs/download-ontology/; last accessed 13-1-2021.</p>
          <p>A borderline case between cultural-linguistic preferences and political bias are the false
friends, where a term in a language has a diferent meaning or connotation in diferent countries
where the language is spoken, due to historical diferences across countries. For instance,
‘herd immunity’ is a common term in American and British English, but is being rebranded
as ‘population immunity’ in South African English, since the former has the connotation of
non-human animals that people do not want to be associated with. It is also diferent in other
languages; e.g., in Spanish, it is inmunidad de grupo and Dutch groepsimmuniteit, i.e., ‘group’
immunity rather than ‘herd’. Note that this semantic shift is distinct from mere synonym
confusion, such as the Football Ontology by name being ambiguous about whether it refers to
the soccer football or American football, and orthographic diferences (e.g., color vs colour) that
simply can be accommodated in the ontology with labels and finer-grained language-coding
schemes (e.g., @en-uk and @en-us etc.).</p>
          <p>Pushing a monolingual ontology or one that has a ‘standard’ natural language for naming
entities then at least amounts to imposing one particular viewpoint or schema and any bias that
comes with it. The chance that a monolingual ontology development team from one cultural
identity in one country builds in such a bias is substantial, and it can be reduced by constituting
a more diverse team of ontology developers who at least speak several languages among them.
Any bias built in may be intentional or unintentional.</p>
        </sec>
        <sec id="sec-2-4-4">
          <title>2.4.4. Socio-cultural Factors</title>
          <p>This concerns hows society is organised, with the assumptions that underlie it and history how
it came about, and any practical efects it may have when developing the ontology. This may be
organisational structures, who lives with whom, demographics, allocation of resources, or social
geography that influences what is salient and what not. For instance, who can marry whom
and how many is a well-known point of variation across the world, which can cause dificulties
for multinational organisations to harmonise that in one system by means of an ontology of
organisations. For instance, it may be a company policy that one can insure the spouse of the
employee, requiring a statement alike Employee ⊑ ∀marriedTo.Spouse, but should the model
also include Employee ⊑ ≤ 1 marriedTo.Spouse, i.e., at most one spouse? Should the gender of
the spouse be recorded? Any answer has at least a perspective, if not a bias, embedded in it.
For an ontology to be universal, the most permissive constraint would be represented, and any
stricter constraints will have to go into the conceptual data model for the database.</p>
          <p>A concrete example is the relatively popular GoodRelations Ontology for e-commerce [28].
It lists several payment methods, but limits the ‘on delivery’ to cash only, even though cash-less
options are also possible (e.g., a pre-paid card or QR-code), which is an accepted method of
payment in areas where robberies are common (although it cannot be excluded that the omission
was due to ‘ran out of time’). Also, its Business requires that they are legally registered, which
may well hold in Europe where the ontology was developed, but in many other countries there
is a vast network of the informal economy that does trade online with their smartphones and it
has no specific opening hours either.</p>
          <p>Socio-cultural factors may also influence the content of medical terminologies, such as the
perception of alcohol use across cultures, and what qualifies as having a drinking problem.
A recent example is demonstrated by a comparison between the Diagnostic and Statistical
Manual of Mental Disorders and the International Classification of Diseases, and their versions
DSM-IV, DSM-V, and ICD-10 in particular, on issues with alcohol intake, where the criteria were
changed. Based on the same data, it resulted in an increase in Alcohol Use Disorder using DSM-V
compared to the DSM-IV criteria. This was primarily due to lowering the threshold for the
number of diagnostic criteria (properties) required for it and increasing the number of criteria
through replacing one class with four new classes that were arguably features of it [29]. This
modification in the lightweight ontology has been blamed on a combination of socio-cultural
factors and scientific disagreement [30].</p>
        </sec>
        <sec id="sec-2-4-5">
          <title>2.4.5. Political and Religious Motivations</title>
          <p>The line between societal bias, political, and religious may be dificult to draw depending on
the case. Aforementioned DSM, which ought to be based on science, was not entirely and likely
was influenced by religious viewpoints at least in some instances. Since the separation between
state and church may not be all that strict, it practically may not be possible to disentangle
the two. A clear-cut case, however, is where the entity type Aggrieved group, as a neutral term,
enters the ontology as Terrorist organisation as preferred label. Concretely, there are terrorist and
terroristgroup in the terrorism ontology of [31], compared to an ActorEntity with various types
of Insiders and Protestors in the Cyberterrorism ontology of [26].</p>
          <p>As with society and language matters, these issues more easily come to light if the team of
ontology developers is diverse or at least has diverse knowledge to bring in. Also here, such
diferences may be intentional or not.</p>
        </sec>
        <sec id="sec-2-4-6">
          <title>2.4.6. Economic Motivations</title>
          <p>The, perhaps, most well-known arena where economic motivations play a role, is the recognition
of something as a disorder or disease, from which follows whether it deserves at least funding
of a treatment if there is one, as well as resources for prevention and research. The Obesity
Society’s panel of experts even stated this bluntly as the main reason in favour of classifying
obesity as a subclass of disease [32]. Its recognition is good for big pharma and possibly also
the patients, but costly for insurers, which results in tension. For the ontology, it means that it
is either included or not, whose decision propagates to electronic health records that make use
of the ontology to annotate findings and propose treatments, and when they are linked to the
pharmacy and the health insurer’s databases. These issues are well-known and therefore are
classified as explicit biases, as deviations to the norm.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Cognitive Biases Assessment: the COVID-19 Ontologies</title>
      <p>The aim of the evaluation is to assess bias in ontologies systematically beyond the selected
examples in the previous section. In particular, to examine it on a set of ontologies in the same
subject domain so that consequences of cognitive bias on the same task might be assessed. Also,
since there are several ontologies in that given domain, at least diferences in perspective may
have been a reason to develop another one. In narrowing down the choice for selection of core
or domain ontologies to assess, we note that there are a few on time and measurements, many
on health and medicine (e.g., 37 are contextualised in [33]), data mining, organisations and
government, and others, which are more or less stable and more or less maintained. Among
the sets of same domain, it is narrowed down to ontologies that are under active development
and, ideally, from the same timeframe so that there has been less chance of mutual influence
(and setting aside the caveat that any biases observed may have been resolved in the meantime).
And, as last criterion, in a domain that the author has suficient knowledge about. Applying
these criteria, it resulted in the selection of the three COVID-19 ontologies that were developed
in 2020. The next section contextualises each ontology and thereafter they are assessed.</p>
      <sec id="sec-3-1">
        <title>3.1. Ontology Descriptions</title>
        <p>The Coronavirus Infectious Disease Ontology (CIDO) [24] is an ontology that was developed
within the OBO Foundry approach [34]. This entails community-based development and reuse
of OBO Foundry ontologies, such as the Infections Disease Ontology that in turn is linked
to the top-level ontology BFO [16]. The scope of the ontology was aimed at knowledge and
information about the SARS-CoV-2 virus and host taxonomy data, its phenotype, and drugs
and vaccines to foster data integration. CIDO v1.0.109 was used for the assessment, to keep
with the time frame where all ontologies were released around July-August 2020; specifically,
cido-base.owl (downloaded on 20-7-2020) with the relevant imports was assessed. It contains
82 classes, 15 object properties, no data properties, and one individual, and 90 logical axioms and
is within the OWL Full profile due to undeclared annotation properties and a few undeclared
classes; logically, it is expressible in the Description Logic ℒℰ ℋ, i.e., it is a basic hierarchy
with existentially quantified properties and an occasional nominal.</p>
        <p>The COviD-19 Ontology (CODO) [35] has as purpose to assist in representing and publishing
of COVID-19 data from the disease course perspective and has subject domain scope COVID-19
cases and patient information. That is, it aims to be a component in IT systems for healthcare.
The CODO V1.2-16July2020.owl was used for the assessment, which contains 51 classes,
61 object properties, 45 data properties, 56 individuals, and 463 logical axioms. It is within the
OWL 2 DL profile, and ℋℐ() more specifically, i.e., it is an expressive ontology that
uses many of the OWL 2 DL constructs available in the language.</p>
        <p>The Coronavirus Vocabulary (COVoc) was developed by the European Bioinformatics Institute
and has as purpose to support navigating and curating the literature on COVID-19, and in
particular the scientific research of it. Documentation of its rationale is available as a workshop
presentation [36]. Its first, and latest, released version is slightly later than that of CIDO
and CODO, although all had their drafts in June 2020, which did not afect its contents. The
covoc.owl was used for the assessment (d.d. 28-8-2020), which contains 541 classes, 179 object
properties, no data properties or individuals, and 672 logical axioms. It is within the OWL Full
profile due to a subset property issue with the annotation properties; just the logical theory is
expressible in ℒℋℐ. In practice, it means it consists of a basic hierarchy with existentially
quantified properties and a few subproperties and inverses.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Bias Assessment</title>
        <p>The presence and absence of the diferent types of bias are summarised in Tables 2 and 3, and
will be discussed in the remainder of this section.</p>
        <p>Bias (Source/type)
Philosophical
Purpose
Science
Granularity
Linguistic
Socio-cultural
Political or religious
Economics</p>
        <p>CIDO
+
–
–
±
+
+
+
–</p>
        <p>CODO
–
+
–
+
–
+
+
–</p>
        <p>COVoc
+
+
+
+
–
+
+
±</p>
        <p>Bias (Cognitive biases from Dimara et al’s list)
Mere exposure/familiarity</p>
        <p>(choice is influenced by exposure to it and thus familiarity with it)
Negative interpretation</p>
        <p>(judgement is afected more by negative information than positive)
Optimism</p>
        <p>(more positive predictions for oneself than for others)
Naive realism</p>
        <p>(the belief that you experience objects in your world objectively)
False Consensus</p>
        <p>(Overestimating that other people are and behave like you and agree
with your opinion)
Illusory truth efect
(a statement is considered to be true after repeated exposure to it)
There are two socio-cultural biases in the CIDO. First, there is a COVID-19 diagnosis class with
three subclasses: negative, positive, and presumptive positive. There are two aspects that stem
from the negative interpretation cognitive bias. First, the [disease]-positive/negative labeling has
clear HIV connotations with stigmatisation and ostracisation from its worst times when little
of it was understood. Test outcomes and diagnoses easily could have been the more common
‘infected’, ‘detected’, or ‘present’ and ‘not infected/detected’ or ‘absent’, alike a patient has a flu
or meningitis infection but is not meningitis positive or flu negative. Second, the presumptive
positive portrays a negativity bias as well, by playing into people’s fears and would brand people
that are statistically unlikely to have been infected, since the WHO guideline is at most 5%
positivity rate and countries aim for that. Neutral and accurate terminology would be, e.g.,
‘pending’, ‘awaiting test outcome’, or ‘under investigation’.</p>
        <p>Conversely, an unwarranted optimism bias is reflected in COVID-19 experimental drug in clinical
trial ⊑ COVID-19 drug, noting that COVID-19 drug ⊑ ∃treatment for.COVID-19 disease process is
asserted in the ontology, and thus entails that COVID-19 experimental drug in clinical trial is a
drug already and is being part of regular treatment processes of COVID-19, since the property
of ∃treatment for.COVID-19 disease process is inherited down into the hierarchy. This is wishful
thinking. A substance under investigation that is being evaluated is not necessarily efective or
safe and for it to be a drug, it has to be efective and approved by the regulatory body.</p>
        <p>A minor language note is drive-thru instead of drive-through for testing stations, but this can
easily be addressed by providing alternative labels. The naming of SARS-CoV-2 also as the
Wuhan virus, however, reflects a political stance, as the term was rarely used outside the USA
since it was advocated by former President Trump and his policies toward China. The FDA
EUAauthorized organization as the only other organisation as sibling of drive-thru COVID-19 testing
facility may, in a lenient reading, be argued to be an instance of ran-out-of-time, considering
that the authors of the accompanying paper [24] have afiliations from diferent countries who
may intend to add their FDA counterpart, or be a familiarity/mere-exposure cognitive bias and a
granularity issue.</p>
        <p>The philosophical view is evident by its embedding in the OBO Foundry [34], its reuse of
ontologies within that framework, such as OBI and IAO, and the organisational principles how
the ontology is structured, which follows the BFO foundational ontology design principles [24].
BFO being founded on the realism stance, content in the ontology may be subject to the naïve
realism cognitive bias. The reuse may be categorised as a mere-exposure cognitive bias, which is
by design and Foundry principles, and thus explicit.</p>
        <p>In sum, CIDO takes the science angle to representing knowledge about COVID-19, but with
a few biases toward USA-centrism, which reduces its of-the-shelf potential. Or: possible CIDO
adoption in Europe or any of the key Global South countries with ample research, testing, or
production capacities, such as India and South Africa, requires modifications to CIDO first.
3.2.2. CODO
The CODO fares slightly better than CIDO on the Laboratory test finding, which can be negative,
positive, or pending. It does have the well-known issue with representing gender or sex, which
is represented as Gender type ≡ {Female, Male} in CODO. A clear socio-cultural bias axiom in
the ontology is InfectedSpouse ⊑ InfectedFamilyMember and InfectedFamilyMember ⊑ Exposure
to COVID-19. This may indicate omissions or time constraints, since the only family member
that can be infected is the spouse according to CODO. It does allow for more family members
by means of subproperties of hasRelationships, but it is not linked to the Exposure class. More
importantly for epidemiological control, is the cultural viewpoint jointly with the consensus bias
by centering on the concept of the (nuclear) family with parents and their children. Globally
more broadly applicable is the notion of household that admits a wider range of composition,
such as live-in grandparents, cousins, nannies, domestic workers, and so on, but where spouses
may not live together in one household due to being a migrant worker. Such complexities in the
context of COVID-19 are recorded and investigated [37], so if CODO were to be used elsewhere,
then this branch needs revision.</p>
        <p>CODO’s purpose is implicated by its abundant use of data properties; hence, it is more alike a
model for recording data than for representing the science of COVID-19 or SARS-CoV-2; e.g.,
in shorthand notation for domain and range axiom, heartrate ⊑ Vital signs × xsd : integer,
which is alike Option B in Section 2.3. A substantial amount of information may be usable
across countries trying to record data about patients. One class is specific to the country of its
developers, India, which is the Mild and very mild COVID-19, which is one of the three categories
mandated by its government rather than the modellers’ granularity bias, which the ontology
developers noted in the annotations of Patient.
3.2.3. COVoc
COVoc clearly states that its purpose is COVID-19 “scientific literature triage”. Knowledge
organisation systems for literature annotation prioritise facilitating that process over ontological
precision or correctness. COVoc’s contents are not clearly structured as a result, in the sense
that there are many top-level terms and mixing of classes and instances. Some aspects, such as
the use of the IAO and import of the RO, may indicate some leaning to the OBO Foundry stack
as philosophical bias or a mere-exposure cognitive bias, since one of the COVoc authors is also
an IAO contributor.</p>
        <p>Its contents regarding cognitive bias raises several questions. One is of granularity, and
perhaps also focus or time, which are straightforward omissions, such as listing only two
continents, Asia and Europe, even though there are 4-7 (depending on how one categories). It
is a mixture of omission or granularity and politics regarding the countries, since there are 10
subclasses of Country, of which two are disputed (Hong Kong and Taiwan) and one is definitely
an error, since West Africa is not a country but a region on the African continent.</p>
        <p>The low-hanging fruit for cognitive bias detection with science as source is Virus ⊑ Organism,
because a virus is not an organism no matter its repetition in popular media, i.e., this would
be an illusory truth efect bias . Medically, the easy bias observation are that there are several
disorders that are represented as subclasses of Disease, such as headache disorder ⊑ Disease,
whereas they are distinct medically, although some organisations would like to see certain
disorders classified as a disease. If there were economic motivations, then the latter is a good
candidate for bias source. One may be tempted to brush them of as mere modelling mistakes
based on layperson commonsense assumptions and ran-out-of-time, but that is precisely where
cognitive bias operates, and this is problematic especially for an ontology for scientific literature.
Further scientific perspectives are built in by recording symptoms, such as Cough and Diarrhea
as subclasses of phenotype, with phenotype defined as “The detectable outward manifestations
of a specific genotype.”. This a very gene-centric view on the body.</p>
        <p>Gender is not present, but biological sex is. The only biological sex recorded in COVoc is
male. Published literature on women and COVID-19 easily dates back to March 2020 (e.g., [38]),
however, which is well before COVoc’s development. Hence, it is, at best, an issue of granularity
and possibly also socio-cultural since the gender bias in medical research is well-known [39].</p>
        <p>Since many terms are plain science terms, like replicase polyprotein 1a (BtCoV) and cryogenic
electron microscopy, there are no obvious language or linguistic issues in the sense of bias, other
than an English language bias that nearly all extant ontologies have.
Having observed that there are indeed cognitive biases in ontologies, does it really matter?
There are several ways where it can afect outcomes in information systems, with the three
principle ones being due to omissions, incorrect attributions, and undesirable deductions that are
logically correct but not ontologically or not according to the other bias.</p>
        <p>Omissions and incorrect attributions have a direct efect on data analysis, since they increase
the amount of noise (technically speaking) when the ontology is used for ontology-based data
access and literature annotation and search. For instance, while mortality rates of men are
higher for COVID-19, relatively more women get infected. If that cannot be annotated, since
absent in COVoc, then searches on the emerging literature will obtain poorer query answers for
possible causes as to why women are tested positive more often than men. Similarly, the lack of
the concept of household, or at least more family members, in CODO, prohibits finer-grained
recording of the chain of infection and thus more likely to lose control of the spread of the virus.</p>
        <p>Incorrect attributions happen when an annotator cannot find the desired knowledge in the
ontology and then uses something else for it. For instance, if Ireland were to use CIDO, then
the walk-through testing facility at Dublin Airport can be approximated by CIDO’s drive-thru in
the sense of passing by, or FDA authorised in the sense of being an oficial test location. More
generally: annotators choose approximations based on diferent criteria, so any data analysis
then will both miss instances and have false positives. Also, a presumptive positive annotation
is, on the whole, an incorrect categorisation about 95% of the test cases (with the aim of ≤ 5%
test positivity rate) and it would seriously distort epidemiological investigations and overload
tracking and tracing eforts if all presumptive positives had to be followed up. As long as
an ontology does not fully characterise all required properties of an entity type so as to be
suficiently semantically precise, there is a heavier reliance on the mere term, which is an easier
target open to multiple interpretations, image schemas, or bias.</p>
        <p>An example of an undesirable deduction resulting from a cognitive bias built into an ontology
can be readily seen with CIDO’s experimental drug (recall Section 3.2.1). Take a data integration
scenario with ontology-based data access, as illustrated in Fig. 1, where each class in the ontology
is mapped to a query over the associated databases. A query over the ontology then avails of
those mappings to retrieve the answer, together with the knowledge represented in the ontology.
Hydroxychloroquine is still used as an experimental drug in COVID-19 clinical trials5, so then
the query “retrieve all COVID-19 drugs” will include in the query answer hydroxychloroquine,
since it recursively retrieves the instances down in the class hierarchy for all COVID-19 drug
subclasses. It is definitely not a drug to treat COVID-19, however, nor has it been approved for
that purpose in any country.</p>
        <p>None of the COVID-19 ontologies have any meaningful deductions similar to the protein
phosphatase experiment that deduced a novelty for human understanding of it [40], nor are
they aimed at achieving that at present. Conversely, on detecting inconsistencies, any issues
with typical sources of problems would likely surface during ontology development already
rather than at runtime in applications, since the reasoner will return an error or an undesirable
5There were 24 active trials with it for COVID-19 (of the 47 in total) https://clinicaltrials.gov/ct2/results?term=
Hydroxychloroquine&amp;Search=Apply&amp;recrs=d&amp;age_v=&amp;gndr=&amp;type=&amp;rslt=; last accessed on 15-1-2021.</p>
        <p>COVID-19</p>
        <p>drug</p>
        <p>COVID-19
experimental drug
COVID-19 experimental
drug in clinical trial</p>
        <p>Mapping: SELECT Drug FROM fda
WHERE Condition = ‘COVID-19’;</p>
        <p>FDA
database
Mapping:
SELECT Intervention FROM CTgov</p>
        <p>WHERE Condition = ‘COVID-19’;
ClinicalTrials.gov
database</p>
        <p>Query
“retrieve all
COVID-19 Answer
drugs”
deduction. For instance, if a developer adds that sentient beings are either human or other-animal
and someone else wants to add plant, then this is caught during that development step already
before deployment. Alternatively, a light-wight ontology language is used from the start so that
such disagreements do not surface due to lack of language expressiveness, notably because of
the absence of disjointness and qualified cardinality constraints. Therefore, our expectation
is that the efects of bias with respect to reasoning consequences may be more salient in data
management and retrieving information rather than in reasoning over the TBox.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>5. Conclusions and Future Work</title>
      <p>Bias may be present in an ontology, a number of which can be categorised as cognitive biases.
Eight categories of sources of bias for ontologies were identified and illustrated: philosophical,
purpose, science, granularity, linguistic, socio-cultural, political or religious, and economic
motives. Four of them are explicit, and the other four may be either explicit or implicit. Three
COVID-19 ontologies that were developed at the same time by diferent groups were assessed
on these types of bias, which showed that each one exhibited a diferent subset of the sources of
bias. This first characterisation and comparative assessment may contribute to further research
into cognitive bias, and therewith also potential ethical aspects of ontologies, both regarding
the modelling component and how it afects their use in applications.</p>
      <p>
        The work presented in this paper aimed to ofer initial steps to explore what bias in ontologies
may amount to, in a more than anecdotal manner. Besides a sensitisation to the topic, it, perhaps,
raised more questions than it ofered answers. A relatively easy addition would be methodical
and software support to note any explicit biases either as annotation in the ontology or in its
documentation. A rigorous method involving interrogation of modelling choices during the
ontology authoring stage may be beneficial, perhaps guided also by a relevant subset of Dimara
et al’s [
        <xref ref-type="bibr" rid="ref11">11</xref>
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cognitive bias from a case of innocuous ran-out-of-time and from a modelling mistake and
attendant ontology quality issues that have other causes. Further ontological investigation into
cognitive bias and its definition would also be useful, since a narrow definition with ‘norm
deviation’ may not be operationalisable for ontologies outside science and engineering.
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