=Paper=
{{Paper
|id=Vol-2952/paper_302a
|storemode=property
|title=Challenges in Legal Process Discovery
|pdfUrl=https://ceur-ws.org/Vol-2952/paper_302a.pdf
|volume=Vol-2952
|authors=Hugo A. López
|dblpUrl=https://dblp.org/rec/conf/bpm/Lopez21
}}
==Challenges in Legal Process Discovery==
Challenges in Legal Process Discovery⋆
Hugo A. López1
Department of Computer Science
University of Copenhagen⋆⋆
Abstract. One of the main promises of process conformance is the op-
portunity to align normative processes (i.e. how the process should be-
have) and event logs (i.e. how does the process actually behaves). Results
of conformance checking are valid as long as normative processes corre-
spond to actual norms. Recent developments advocate the use of Natu-
ral Language Processing (NLP) to process model discovery from texts.
We present a series of challenges in textual process discovery that limit
its applicability to real norms. The challenges emerges from experiences
with legal practitioners in the digitalization of administrative processes
in Danish and Italian municipalities, and they need to be solved in order
to provide accurate normative processes that reflect the intent of laws.
Key words: Natural Language Processing, Normative Processes, Pro-
cess Discovery, Process Conformance
1 On (legal) process compliance and normative models
More than thirty years separate us from Sergot’s seminal work on Compliance
by Design [1]. In principle, the compliance problem remains the same: given a
law, ensure that all executions of a process behave in accordance with the rights
and obligations there established, and that it never allows the violations ruled
in the law. Specifically, this requires us 1) to provide a formal representation of
laws, 2) to establish a formal link between legal policies and events in a process,
and 3) to verify that the execution of events does not violate the specification.
Process compliance is close to the heart of BPM, where processes operate in
environments heavily regulated such as manufacturing, banking or healthcare.
However, while decades of research have looked at the semantic representation
of norms and compliance verification, fewer efforts have been placed in the elic-
itation of normative policies for compliance. Laws are declarative artefacts that
contain events, decisions, rights, obligations, violations and relations between
them. Assuming a representation framework for the specification of laws (either
in terms of logics [1, 2, 3, 4], or models [5, 2, 6, 7, 8]), how are formal policies
related to the legal articles in a law?
Rather than focusing on expressiveness considerations in compliance lan-
guages (that have been covered in different surveys, e.g. [9]), our focus is on
⋆
Copyright ©2021 for this paper by its authors. Use permitted under Creative
Commons License Attribution 4.0 International (CC BY 4.0).
⋆⋆
Work supported by the Innovation Fund Denmark project EcoKnow (7050-00034A)
2 Hugo A. López
mechanising the mapping between a (textual) law and its formal representation.
Legal specialists are not trained in compliance languages and they need support
to generate formal representations of the law. This requires a triple effort: first,
they need to parse the law and identify which fragments can be formalized, sec-
ond, for each candidate rule, encode the fragments in terms of a formal specifica-
tion that is semantically equivalent (modulo theory) to the original text. Finally,
such interpretations need to be validated so there is a congruence between the
possible worlds encoded in the specification, and the legal interpretation. Thus
our problem, in short, is:
How can we discover normative models that preserve the intended se-
mantics of laws in a time-efficient way?
The challenges reported in this paper result from 4 years of interactions
between the author and municipal sectors in Denmark and Italy in the formal-
ization of laws using DCR graphs in the EcoKnow project [10]. The challenges
presented here are not particular to a modelling notation and thus they corre-
spond to any modelling technique used to generate normative models.
2 Elicitation of normative models via NLP
NLP is a key enabling technology for solving our question. Instead of discovery
from event logs, NLP allows the identification of processes from texts. This is nec-
essary for the discovery of normative models as ambiguity, length and complexity
of laws hinder discovery results. While discovery techniques present encouraging
results for (short, imperative) process descriptions, there is no evidence of its
application to laws. Moreover, initial application of discovery methods in indus-
trial settings reveals that there is still work to mature the technologies [11]. The
challenges emerged from interactions with case workers, lawyers and consultants
with domain expertise in danish and italian laws. They resulted in the elicita-
tion of an annotation guideline as an initial step to create corpora containing
manually assigned process-law pairs [12]. Our initial experiments in the Dan-
ish laws included annotations of 55 articles from the danish administrative acts
for family and social services [13]. In the italian case, we focused on municipal
laws governing the release of construction permits [14]. Both groups performed
textual annotations of laws into process elements, with a follow-up including
interviews and think-out-loud sessions. The most interesting challenges follow:
2.1 Challenges for general textual process discovery
Challenge 1: The process in the law Any law contains several pages of text
combining technical and non-technical information. Technical information refers
to rules and procedures required to generate a legal outcome. In a sense, this
is related to the (deontic) logics, whose aim is “the study of those sentences in
which only logical words and normative expressions occur essentially. Normative
Challenges in Legal Process Discovery 3
expressions include the words ‘obligation’, ‘duty’, ‘permission’, ‘right’, and re-
lated expressions” [15]. A discovery algorithm needs to select only the technical
information in the law, filtering non-process information to avoid false-positives.
Challenge 2: Adequate process representations Most textual discovery
methods assume that their inputs are imperative processes. For instance, pars-
ing techniques in [16, 17] assume constructs such as start and end nodes. This
information does not exist in laws: some rights are inherent, and they are valid
for as long as their clauses remain valid.
Challenge 3: Sentence ambiguity Most works on automated process discov-
ery rely on syntax-driven parsing (SDP) where building the abstract syntax tree
is important to generate the formula representation of the process [18, 19, 20].
However, SDPs do not consider ambiguities in the semantic of the sentence. For
example:
If the agent has completed his additional support and the clerk has issued the
money order, the clerk closes the claim.
and
The claim is closed by the clerk if additional support is completed by the agent
and the money order is issued by the clerk.
Contain the same rule pattern with antecedents (the agent) completes addi-
tional support and (the clerk) issues money order, and consequent (the clerk)
closes the claim. This challenge is of particular importance in laws: they are
typically written in passive voice, complicating the identification of atoms and
rules. The introduction of passive and active voice sentences created divergence
in the way legal annotators produced atoms and rules, leading to challenges in
interannotator agreement in similar way than law annotations [21].
Challenge 5: Textual process discovery metrics While there is a standard
set of measures to benchmark process discovery algorithms for logs [22], there
is no consensus on what will be the measures for textual process discovery.
The algorithms in [16, 18, 19, 23] all differ in the target modelling language.
While each work provides an evaluation in terms of precision, measurements like
fitness cannot be applied since there are no explicit traces. In our experience
with lawyers, normative models are tested for validity based on their abilities to
replicate legal precedents, that is, previous cases from the law [8].
2.2 Challenges specific to process discovery of legal texts
Challenge 6: What is a legal event? Most works in process discovery using
NLP start considering linguistic patterns in [16] to identify events and activities.
Here it is assumed that activities are written in a verb-object pattern (e.g.:
pay compensation for loss of earnings). Discovering legal events requires us to
extend this notion to rights and obligations. Sometimes, event detection will
acknowledge the formal recognition for which an event has been performed, as
in “Compensation shall be subject to the condition that the child is cared for
at home as a necessary consequence of the impaired function” [24].
Such forms do not correspond to linguistic patterns in the state of the art.
4 Hugo A. López
Challenge 7: Policy-formula mismatch A common textual process discovery
technique is the identification of stopwords [25]. Our experience is that stopwords
are a necessary but not sufficient condition for semantic rule discovery. Assume
an interpretation in Linear Temporal Logic3 . A response pattern is modelled as
the LTL formulae G(A → FB) and it is associated with an obligation: In all
cases, if A is executed, there exists an eventual execution of B. For example:
The municipal council shall pay compensation for loss of earnings to
persons maintaining a child under 18 in the home whose physical or
mental function is substantially and permanently impaired
While the formula G(maintainChildU nder18(X, Y ) ∧ physicalM entalImpairment(Y ) →
FP ayCompensation(X)) is expressible in LTL, the interpretation will be con-
tested by a lawyer as this allows a payment on the negation of the antecedents.
Modifying the interpretation (e.g. adding a condition relation between the an-
tecedents and the consequence) does not generalize for all uses of “shall”. Inter-
pretations are context-dependent.
Challenge 8: Compositionality Laws are not monolithic artefacts, and cre-
ating specifications from them need compositional operators. For example, in:
CASS 48.–(1) Before the municipal council makes a decision under sec-
tions 51–63, section 65(2) and (3) and sections 68–71 and 75,
the child or young person must be consulted on these matters.
The model can only be expressed if we can compose §48 with §51, 52, etc.
3 Initial ideas towards solving the problem
We believe that there is still a great deal of work to do in order to make business
processes mining from text work in industrial cases. Solving the first 5 challenges
require a synergy between the NLP-BPM community to release resources (e.g.:
corpora, models) for inspection and benchmarking. Moreover, we advocate for a
co-created approach to textual process discovery. Rather than building the most
accurate set of parsing rules, it is important to i) Embed expert knowledge on
what is important in discovery, ii) Disambiguate texts, and iii) Implement tech-
niques that can learn from users. From the language perspective, we see a grow-
ing interest in declarative process discovery techniques based on DECLARE [18],
ATDP [26] and DCR graphs [23]. They can be adapted in the context of laws.
Tools like the Process Highlighter [27] or the Model Judge [28] allow us to filter
what should be captured as process information (challenge 1), capture knowl-
edge such as what constitutes an event (challenge 6) and the semantics of legal
rules (challenge 7). Tools might benefit from the integration with legal event
detection [29] and norm-type classifiers [30, 31].
A second enabler to make discovery usable are language models trained
in laws (challenge 3). While general-purpose models (e.g. BERT [32]) capture
3
The same pattern appears in other languages, e.g.: DCR graphs
Challenges in Legal Process Discovery 5
context-dependency and short-ranging references, they might give wrong results
due to the variety of texts they are trained on. Scalability is a factor to consider:
the attention layers in transformer architectures scale quadratically. This limits
the length of textual analysis and imposes limitations for discovery.
Third, dialogue systems can provide feedback to users about the semantics of
each sentence. Surface patterns are indicators of intended meanings [31] that can
be refined by presenting characteristic traces. This is fundamental to refine the
mappings from surface text to formal semantics, thus reducing misinterpretations
(challenge 7). Event-log generation from texts [26] might be able to contrast
exemplary traces with user’s intended meaning.
Finally, a necessary step for discovery is the integration of parsers based on
formal meaning representation (MR) frameworks [33]. MR aim to represent texts’
formal structure (e.g. graph-based meaning representations), reducing parsers
imprecision in sentence variants with the same intended meaning (challenge 3).
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