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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Peeking Outside the Black-Box: AI Explainability Requirements beyond Interpretability</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Jakob Droste</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Hannah Deters</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ronja Fuchs</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Kurt Schneider</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Leibniz University Hannover, Software Engineering Group</institution>
          ,
          <addr-line>Hannover</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>With the rise of artificial intelligence (AI) in society, more people are coming into contact with complex and opaque software systems in their daily lives. These black-box systems are typically hard to understand and therefore not trustworthy for end-users. Research in eXplainable Artificial Intelligence (XAI) has shown that explanations have the potential to address this opacity, by making systems more transparent and understandable. However, the line between interpretability and explainability is blurry at best. While there are many definitions of explainability in XAI, most do not look beyond the justification of outputs, i.e., to provide interpretability. Meanwhile, contemporary research outside of XAI has adapted wider definitions of explainability, and examined system aspects other than algorithms and their outputs. In this position paper, we argue that requirements engineers for AI systems need to consider explainability requirements beyond interpretability. To this end, we present a hypothetical scenario in the medical sector, which demonstrates a variety of diferent explainability requirements that are typically not considered by XAI researchers. This contribution aims to start a discussion in the XAI community and motivate AI engineers to take a look outside the black-box when eliciting explainability requirements.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Explainable Artificial Intelligence</kwd>
        <kwd>Interpretability</kwd>
        <kwd>Requirements Engineering</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        In modern society, AI permeates an increasing range of professional and personal spaces.
Intelligent software systems are used by companies and private end-users alike. These systems
are often opaque in nature and are referred to as black-boxes [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], as their inner workings are not
visible and understandable to the average observer. As they are commonly used in safety-critical
environments, such as autonomous driving [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] or the medical sector [
        <xref ref-type="bibr" rid="ref3 ref4">3, 4</xref>
        ], it is necessary for
these systems to be transparent and trustworthy for their users. The research area of XAI
aims to address this issue, by providing explanations that help end-users understand the AI
systems they are working with, and by providing transparent reasoning for the AI systems’
behavior and decisions. This is also referred to as providing interpretability [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. In this paper,
we argue that explainability as a non-functional requirement (NFR) goes beyond just providing
interpretability. To this end, we identify three types of needs for explanations that are typically
not covered by XAI research and engineering: privacy information, system interaction and
domain-related information. To demonstrate the applicability of these explainability needs to AI
systems, we discuss a use case of image recognition and classification algorithms in the medical
sector. The goal of this contribution is to raise awareness for AI explainability requirements
outside of providing interpretability, and to motivate discourse among XAI researchers and
engineers about explainability as an NFR.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Interpretability in Explainable Artificial Intelligence</title>
      <p>
        Gilpin et al. [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] refer to explainability as a means to achieve interpretability and completeness,
with interpretability referring to system internals and completeness referring to describing the
internal operations of a system in an accurate manner. When the term explainability is used
in XAI papers, authors typically refer to explanations of the model or to the reasoning for its
outputs [
        <xref ref-type="bibr" rid="ref6 ref7 ref8">6, 7, 8</xref>
        ]. In other words, explainability is used as a means to provide interpretability.
      </p>
      <p>
        Interpretability is seen as a means to improve trust and transparency by ofering
humanunderstandable justifications for the decisions made by an AI system by ofering explanations [ 9].
Moreover, explaining model behavior is thought to improve model bias understanding and
fairness [9]. Fan et al. [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] conducted a comprehensive survey on interpretability of neural
networks and compiled a definition of interpretability:
      </p>
      <p>
        Definition: Interpretability refers to the extent of human’s ability to understand and
reason a model. [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]
      </p>
      <p>
        Notably, this definition of interpretability does not go beyond explaining a system’s model
and reasoning. XAI research usually divides all AI explanation methods into local and global
methods [
        <xref ref-type="bibr" rid="ref1 ref7">1, 7, 9</xref>
        ]. Local methods refer to individual data instances and global methods to the
model as a whole. Once again, explaining the model itself is the focus of XAI.
      </p>
    </sec>
    <sec id="sec-3">
      <title>3. Explainability Requirements Beyond Interpretability</title>
      <p>In recent years, explainability has also been researched independently of AI. Mucha et al. [10]
investigated how interfaces for explanations should be designed. Other studies looked into
the personalization of explanations [11, 12]. Chazette et al. [13] investigated the influence of
explainability on related NFRs, such as understandability and usability. Through on a
comprehensive systematic literature review (SLR), they examined diferent definitions of explainability
and derived a general definition of explainable systems:</p>
      <p>Definition: A system S is explainable with respect to an aspect X of S relative to an
addressee A in context C if and only if there is an entity E (the explainer) who, by giving a
corpus of information I (the explanation of X), enables A to understand X of S in C. [13]
Following this definition, explanation can be used to make diferent kinds of system aspects
more understandable. While Chazette et al. [13] do not provide a comprehensive overview of all
explainable system aspects, they name some examples that they identified via their SLR. System
aspects such as the system’s inner logic and its reasoning process are aspects that correspond
to conventional XAI explanations, i.e., they support interpretability.</p>
      <p>However, Chazette et al. [13] also consider a system’s knowledge about its user to be an
explainable system aspect. Explanations that allow users to understand how their personal
information is stored and processed difer from typical XAI explanations. In this context,
Brunotte et al. [14] introduce the concept of privacy explanations as part of explainability.
The need for privacy explanations is also underlined by the works of Hamon at al. [15] and
Jobin et al. [16], that highlight the importance of data protection and privacy in AI systems.</p>
      <p>Chazette et al. [17] also state that explanations can guide users, and that they can make
systems more easily operable. This reveals another type of explanatory need, namely the need
to explain end-users’ interactions with the system. Deters et al. [18] investigated the need for
explanations in a modified social media app and identified that the most common need for
explanations was user guidance. This includes explaining both the navigation and the operation
of a system. Interaction explanations are required when users have a goal in mind and know
what they want to do, but do not know how to achieve this goal within the system.</p>
      <p>Lastly, we consider explanations of domain-specific elements to be part of a system’s
explainability. For example, explanations of specific terminology, that lay users do not know,
could potentially increase the usability of a given system [19, 20]. Chazette et al. [17] stated
that domain aspects have an influence on how explanations should be designed. We argue that
domain-related explanations of specific terms and system elements can support end-users
and can enable the efective use of the system.</p>
      <p>Figure 1 shows the four types of AI explainability requirements identified in this paper. Note
that we do not claim this to be a complete taxonomy and that there might still be more types of
explainability requirements that warrant further investigation. Research into diferent types of
explainability requirements is already ongoing for AI-independent software systems [14, 18].
However, there is a lack of research into explainability requirements specific to AI systems that
do not relate to interpretability. If requirements engineers of AI systems continue to reduce
explainability requirements to the explanation of algorithms and system outputs, important
end-user needs might be omitted.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Exemplary Scenario</title>
      <p>
        To demonstrate the applicability of diferent explainability requirements to AI systems, we
present a hypothetical scenario from the medical sector. In clinical diagnostics, image recognition
algorithms are used to support both medical professionals and their patients. In dermatology
in particular, image recognition and classification is used for the identification of malignant
tissue in suspicious skin areas [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. While there are several particular technologies to enable this,
modern systems in this domain usually rely on machine learning and related AI algorithms [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>In this scenario, we consider two important stakeholder groups that interact with image
recognition systems: medical professionals and lay users. Medical professional like
dermatologists are trained to examine suspicious skin areas and identify malignant tissue such as
melanomas. To support their decision making and avoid fatal errors in diagnosis, they can use
image recognition systems. Lay users, such as patients, may use the same image recognition
technology to get a preliminary diagnosis before they decide whether they want to visit a doctor.</p>
      <p>Diferent kinds of explanations do not have equal significance across these stakeholder
groups. Furthermore, providing inappropriate explanations can potentially cause frustration
and confusion in end-users [17, 21]. To provide appropriate explanations for every stakeholder
group, the diverse explainability needs of each group must be considered [12]. For example,
medical professionals need explanations on why the system made a certain diagnosis instead
of another. If professionals are not able to understand and verify the diagnoses made by the
system, they might ultimately not trust the diagnoses, even if they are correct. Conversely,
as trained professionals, they need less explanations concerning the operation of the system.
Furthermore, they do not need detailed explanations related to the medical terminology used
by the system, and they do not need in-depth privacy explanations, as long as they know that
their patients’ medical data is not misused.</p>
      <p>Lay users might prefer explanations on how to correctly input the data or on what certain
medical terms mean. If they are unable to correctly navigate the system or provide the necessary
inputs, they might be unable to use the system or they might accidentally make incorrect inputs
that can lead to incorrect diagnoses by the system (e.g. not inputting an appropriate photo of the
suspicious skin area). In contrast to medical professionals, lay users do not understand most of
the medical terminology used by the system. In order to be able to understand a diagnosis, they
need explanations for the medical terminology that is used. As the system uses their personal
medical data, lay users might also want privacy explanations that detail exactly how their data
is stored and processed.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Conclusion and Research Perspective</title>
      <p>Within the field of XAI, explainability is typically reduced to explaining the inner workings of
black-box AI systems, or to justifying their outputs, i.e., to provide interpretability. By providing
insights on how an AI system works and how it reaches its results, XAI engineers aim to increase
the transparency and understandability of the system. In contrast to this, recent research in
explainability requirements outside of AI has shown that there are explainability requirements
that go beyond interpretability. Examples of this are privacy explanations, aiming to foster trust,
as well as interaction and domain explanations, aiming to increase the usability of the system.</p>
      <p>In this position paper, we discussed the applicability of these diferent types of explanations
to AI systems. In particular, we provided the example of image recognition in the medical sector
to show how diferent kinds of explainability requirements can apply to an existing AI use case.
We hope that this demonstration provides the necessary push for XAI researchers and engineers
to take a look outside the black-box, and to start considering explainability requirements beyond
interpretability when designing explainable systems.</p>
    </sec>
    <sec id="sec-6">
      <title>Acknowledgments</title>
      <p>This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research
Foundation) under Grant No.: 470146331, project softXplain (2022-2025).
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