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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <article-id pub-id-type="doi">10.3390/info13110510</article-id>
      <title-group>
        <article-title>Enhancing PLM Performance on Labour Market Tasks via Instruction-based Finetuning and Prompt-tuning with Rules</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Jarno Vrolijk</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>David Graus</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Randstad</institution>
          ,
          <addr-line>Diemen</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Amsterdam</institution>
          ,
          <addr-line>Amsterdam</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2019</year>
      </pub-date>
      <volume>1</volume>
      <fpage>37309</fpage>
      <lpage>37323</lpage>
      <abstract>
        <p>The increased digitization of the labour market has given researchers, educators, and companies the means to analyze and better understand the labour market. However, labour market resources, although available in high volumes, tend to be unstructured, and as such, research towards methodologies for the identification, linking, and extraction of entities becomes more and more important. Against the backdrop of this quest for better labour market representations, resource constraints and the unavailability of large-scale annotated data cause a reliance on human domain experts. We demonstrate the efectiveness of prompt-based tuning of pre-trained language models (PLM) in labour market specific applications. Our results indicate that cost-eficient methods such as PTR and instruction tuning without exemplars can significantly increase the performance of PLMs on downstream labour market applications without introducing additional model layers, manual annotations, and data augmentation.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;taxonomy</kwd>
        <kwd>transformer</kwd>
        <kwd>natural language processing</kwd>
        <kwd>labour market intelligence</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        dations [
        <xref ref-type="bibr" rid="ref7 ref8">7, 8, 9</xref>
        ].
      </p>
      <p>
        Many of these approaches rely on supervised learning,
The increasing availability of raw labour market infor- where a commonly identified limitation in literature is
mation allows businesses, educational facilities and job the availability of multilingual, labour market and
taskseekers to gain a clear and more complete understanding specific datasets. In addition, due to the dynamic nature
of the labour market [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. While the increasing volumes of the labour market makes it very dificult to keep more
of available data provide opportunities, there are several structured representations of the labour market
up-tochallenges towards fully utilizing the data. date and relevant (i.e. labour market ontologies and
tax
      </p>
      <p>On the one hand, the majority of available data is of an onomies); updating and maintaining these knowledge
unstructured nature, with a lack of large-scale annotated structures is typically done by human domain experts,
datasets that could be used in training, and/or fine tun- making them time- and resource-intensive, and meaning
ing of models for downstream applications. On the other that whenever such a structure is updated, datasets for
hand, there is much efort in creating structured repre- supervised learning may become obsolete.
sentations of labour market data, through taxonomies In this paper, we propose a novel method that relies
and ontologies such as ESCO,1 ISCO,2 or O*NET.3 on pretrained language models (PLMs), prompt tuning</p>
      <p>
        Leveraging structured ontologies to enrich and inter- with rules (PTR) [10], and the structured multilingual
pret unstructured labour market data has considerable ESCO taxonomy, to eficiently and cheaply generate large
research attention, through skill and occupation recog- amounts of labeled data for learning a variety of
downnition, classification, and linking [
        <xref ref-type="bibr" rid="ref2 ref3 ref4 ref5 ref6">2, 3, 4, 5, 6</xref>
        ]. These stream tasks for extracting structured information from
diferent downstream tasks can prove invaluable in en- unstructured labour market data, specifically: (i)
relaabling better workforce and labour market insights, iden- tion classifiers, that aim to predict the type of relation
tification of trends and temporal patterns, and providing between skills and occupations, (ii) entity classifiers, that
structured data or enrichments that can be applied as aim to classify labour market entities as skill or
occufeature representation for job or career path recommen- pation, (iii) entity linkers, which aims to link various
surface forms of labour market entities to their canonical
underlying skill or occupation entity, and (iv) question
answering approaches, that aim to answer the
correspondence between a descriptive text and the associated skill
or occupation.
      </p>
      <p>In this paper, we aim to address the following research
questions:</p>
      <sec id="sec-1-1">
        <title>1. Are "out-of-the-box" PLMs capable of generaliz</title>
        <p>
          ing learned behavior to labour market specific
applications? the masked language modelling (MLM) pre-training
ob2. Does instruction, and sub-prompt finetuning a jective, the authors also introduce the so-called ESCO
PLM on a mixture of task-specific (i.e. general and Relation Prediction (ERP) task to internalize knowledge
labour market specific) datasets increase the per- of non-hierarchical relations within ESCO [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ].
formance on labour market specific benchmarks? Another pre-training-based approach that leverages
3. Is the tuned PLM able to transfer the learned be- a self-supervised method to pre-train a deeply joint
havior across labour market specific tasks? language-knowledge foundation model from text and
knowledge graphs at scale is the Deep Bidirectional
        </p>
        <p>In this paper, we demonstrate domain-specific prompt- Language-Knowledge Graph Pretraining (DRAGON)
probased tuning and its efect on the performance of skill posed by Yasunaga et al. [21]. Results from the paper
extraction, occupation classification, link prediction, and indicate that DRAGON outperforms existing LM and
entity linking tasks. We propose leveraging instruction LM+KG models on diverse downstream tasks in
particutuning without exemplars (i.e. no examples at infer- lar on complex reasoning about language and knowledge.
ence time) and sub-prompts for a more cost-eficient Despite the success of fine-tuning PLMs, there is a big
solution for downstream labour market applications gap between the MLM objective and fine-tuning
objec[11, 12, 13, 10]. We provide manually constructed tem- tives for downstream applications. Prompt-based
learnplates that encode the knowledge embedded in the ESCO ing has been a widely explored method that uses
temoccupation and skill taxonomies. We benchmark difer- plates to transform the input into classification
probent configurations of finetuning the PLMs, to demon- lems, and as such, closes the gap between task-specific
strate the efectiveness of e.g., adding instructions or and MLM objectives [22]. [23] propose KnowPrompt, a
sub-prompts. method for task-oriented prompt template construction
where they use special markers to highlight entity
men2. Related Work tions in the template. [24] also proposed a template-based
NER model using BART. The model enumerates all
posRecent successes of PLMs such as GPT [14], BERT [15], sible text spans and considers the generation probability
RoBERTA [16] and T5 [17] have demonstrated the use- of each type within manually crafted templates [22, 24].
fullness and adaptability of the transformer architecture. Since the manual creation of templates is
labourAlthough these PLMs can capture rich knowledge from intensive, methods for the automated generation of
massive corpora, a fine-tuning process with extra task- prompts and labels are well-researched. In principle, a
specific data is still required to transfer their knowledge prompt consists of a template and label words. As such,
for downstream tasks. Besides fine-tuning language mod- Schick and Schütze [13] first searches the label word
els for specific tasks, recent studies have explored better space for the manually created templates. Next,
gradientoptimization and regularization techniques to improve guided search automatically generates both templates
ifne-tuning. and label words. Compared to human-picked prompts,</p>
        <p>Several works try to integrate ontological and/ or taxo- most auto-generated prompts cannot achieve comparable
nomical knowledge into task-specific models, to improve performance [10].
the performance of downstream applications. Take the Prior literature has shown that increasing the
numwork by [18], who introduced KnowBert, a methodology ber of tasks in finetuning improves the generalization to
that explicitly models entity spans in the input text. They unseen tasks [11]. Experiments from Chung et al. [11]
further use an entity linker to retrieve relevant embed- show that "instruction finetuning" scales well with the
dings of the entity from a knowledge base to enhance number of tasks and the size of the model. Wei et al.
their representations. Another approach would be the [25] further suggests that instruction-tuned models
rework by [19], the so-called TransE model, that focused pri- spond better to continuous outputs from prompt tuning.
marily on representing hierarchical relationships. Similar Prompt tuning on FLAN even achieves more than 10%
to our work, TransE models multi-relational data from improvement over a non-instruction-tuned equivalent
knowledge bases (i.e. triplestores) to improve perfor- model [25].
mance for link prediction [19].</p>
        <p>
          [20] took a diferent approach, proposing ERNIE, a 3. Methodology
method that consists of two stacked modules, namely the
T-Encoder responsible for capturing lexical and
syntactic information, and the K-Encoder responsible for aug- 3.1. Preliminaries
menting this lexical and syntactical information with ex- 3.1.1. ESCO
tra token-oriented knowledge from the underlying layer
[20]. Lastly, we have ESCOXLM-R that employ further ESCO (European Skills, Competences, Qualifications and
pre-training on the ESCO taxonomy [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ]. In addition to Occupations) is the European multilingual classification
skill
occupation
....
        </p>
        <p>is an optional skill for
is an essential skill for
....</p>
        <p>skill
....
occupation
MLM Head</p>
        <p>MLM Head</p>
        <p>MLM Head
the
[MASK]
ensure correct metal temperature
[MASK]
the
[MASK]
electron beam welder</p>
        <p>Craft and
related trades
workers
is-a</p>
        <p>Metal,
machinery and
related trades
workers
butt welder
is-a</p>
        <p>welder
atomic welder
is-a
electron
beam
welder
alternativeLabel
isOptionalSkill
ensure correct metal</p>
        <p>temperature
isEssentialSkill
wear appropriate
protective gear
spot metal
imperfections</p>
      </sec>
      <sec id="sec-1-2">
        <title>In this paper we rely on the T5 PLM, since the text-to-text</title>
        <p>framework allows us to directly apply the same model,
objective, training procedure, and decoding process to
of skills, competences and occupations. In total, ESCO every task we consider [17]. In addition, we turn to
describes 3,008 occupations and 13,980 knowledge, skill, an instruction-tuned variant of the T5 model:
FLANand competences in 28 diferent languages. T5. Instruction-based finetuning has shown to improve</p>
        <p>
          ESCO has both hierarchical and non-hierarchical re- zeroshot performance on unseen tasks [25, 11]. In this
lationships: hierarchical relationships, or hypernymies, paper we aim to study whether this property also applies
are relations of the form x is-a y [
          <xref ref-type="bibr" rid="ref4">26, 4</xref>
          ]. Non-hierarchical to the domain-specific unseen tasks that we propose.
relationship are essentially those relationship that are not
hierarchical. For example: “Java Programming is an es- 3.2. Prompt-Tuning with Rules
sential skill for a Software Developer” is a non-hierarchical
relationship, whereas, “a Software Developer is a Infor- In this paper, we utilize the ESCO taxonomy as
backmation and Communications Technology Professional” is ground knowledge for the Prompt-Tuning with Rules
hierarchical. (PTR) approach proposed by Han et al. [10].
PTR builds on prompt tuning methods that rely on
3.1.2. PLMs: T5 &amp; FLAN-T5 cloze tests, where the PLM is applied to replace or fill in a
missing word in a sentence. A so-called verbalizer maps
a fixed set of class labels (e.g., positive, negative) to
underlying label words (e.g., “great”, “terrible”), so that
by predicting a label word, the PLM efectively classifies
a sentence.
        </p>
        <p>PTR extends this prompt tuning approach with prior
knowledge encoding, i.e., leveraging logic rules to encode
prior knowledge about tasks and classes into prompt
tuning, and eficient prompt design, through composing
multiple sub-prompts and combining into prompts [10].</p>
        <p>Q: Answer the following with yes/no
Does "Assign and manage staff tasks in areas such
as scoring, arranging, copying music and vocal
coaching." describe "manage musical staff"?</p>
      </sec>
      <sec id="sec-1-3">
        <title>Illustrative example We illustrate how we leverage</title>
        <p>the ESCO taxonomy to construct and populate
subprompts, as proposed by Han et al. [10]. A: [MASK]</p>
        <p>Consider a (sub-)prompt template for entity type
classiifcation, as; "[CLS] the [MASK] [ENTITY]." Which
can be instantiated for the skill "ensure correct metal
temperature," as: "[CLS] the [MASK] ensure correct
metal temperature," and for the occupation
"electron beam welder," as: "[CLS] the [MASK] electron Figure 2: Visual representation of method: Instruction tuning
beam welder." for the QA examples. The instruction is prepended to the</p>
        <p>Finally, we can combine the above instantiations question, instructing the PLM how to proceed in answering
of the same sub-prompt into a final prompt, that the given question.
spans entity type and relation classification, as such:
"[CLS] the [MASK]1 ensure correct metal
temperature [MASK]2 the [MASK]3 electron compute [11]. Furthermore, Chung et al. [11]
demonbeam welder". strate that smaller models that are instruction tuned can</p>
        <p>PTR relies on so-called "verbalizers" that map class outperform larger models without it.
labels to label words. In our example, the class labels Figure 2 demonstrates how we leverage the ESCO
tax{"skill", "occupation"} for entity classification are mapped onomy to construct instruction tuning templates for the
to (the same) label words {"skill", "occupation"} in place of QA examples.
[MASK]1 and [MASK]3, and the class label
{"isEssentialSkill", "isOptionalSkill"} in place of [MASK]2 are mapped
to the corresponding label words {"is an essential skill 4. Experimental Setup
for", "is an optional skill for"} in the case of relation
classification. The aim of this paper is to leverage prompt-based and
i.e.,  []1 and  []3 aim to assign an en- instruction-based finetuning, to cost-eficiently optimize
tity class through predicting a label word from X, and PLMs performance on four downstream labour market
 []2 aims to classify the type of relation between tasks. As described in the previous section, we propose
the two through label words Y. four diferent tasks for evaluation, namely: entity
classiifcation (EC), relation classification (RC), entity linking
(EL), and question answering (QA).</p>
        <sec id="sec-1-3-1">
          <title>3.3. Instruction-based Finetuning</title>
        </sec>
      </sec>
      <sec id="sec-1-4">
        <title>Instruction-based finetuning aims to teach a PLM to per</title>
        <p>form certain tasks, by responding to instructions in
natural language [25]. For two of our three datasets (i.e.,
the QA and EL), we manually constructed templates that
result in natural language instructions that describe the
task for that dataset to the PLM.</p>
        <p>While scaling language model sizes seems to be a
reliable predictor for improved model performance, it comes
at the price of high compute. Therefore, development of
compute-eficient techniques that improve performance
at the cost of a relatively small amount of computational
resources is important. Instruction-based finetuning
improves performance of PLMs on evaluation benchmarks
by up to 9.4%, requiring only 0.2% of the pre-training</p>
        <sec id="sec-1-4-1">
          <title>4.1. Datasets</title>
        </sec>
      </sec>
      <sec id="sec-1-5">
        <title>We evaluate PTR and instruction-based finetuning in</title>
        <p>labour market-specific downstream tasks through
benchmark datasets we generate through populating
handcrafted templates, with instances from the ESCO
taxonomy.</p>
        <p>We generate three datasets of prompts, that address
four diferent tasks; i) entity classification (EC) and ii)
relation classification (RC) as illustrated above (combined
in a single set of prompts), in addition to iii) entity linking
(EL), and iv) question answering (QA).</p>
        <p>Construction of a self-supervised dataset comprises
three diferent components; i) a subset of ESCO relations,
ii) a template to map the triples associated to the relations
# total
# skills
# occupations
# essential
# optional
# altlabels
# pos
# neg</p>
        <p>EC + RC
123,752
13,890
3,008
64,877
58,875</p>
        <p>123,752
0
to (sub-)prompts, and iii) verbalizers that map class labels
to label words.
4.1.1. Entity Classification + Relation</p>
        <p>Classification</p>
      </sec>
      <sec id="sec-1-6">
        <title>To build the entity classification and relation classifica</title>
        <p>tion (EC + RC) dataset, we leverage the isEssentialFor and
the isOptionalFor relations as found in ESCO. For both
entity classification and relation classification, we largely
follow the work by Han et al. [10], i.e., we extract all
triples that have as subject a skill entity, the
isEssentialFor or the isOptionalFor as predicate, and finally as object
an occupation entity.</p>
        <p>Formally, our triples look as follows:
&lt; , ,  &gt;,
(1)
where  ∈ { ,  }. The
entity and relation classification template  () is
formalized as:</p>
        <p>1 =  ℎ [ ]  []
2 =  ℎ [ ]  []
where
1 [ ] 2
relation classifications we have not included the
possibility of "no relation" and/ or "no entity", for the simple
reason of self-supervision. While we fully believe these
negative examples to be useful for better learning how
to recognize entities and the relation connecting entities,
they would require manual annotation, and as such fall
beyond the scope of this research.
4.1.2. Entity Linking</p>
      </sec>
      <sec id="sec-1-7">
        <title>To model entity linking, we rely on the alternativeLabel</title>
        <p>relation in ESCO, i.e., our task is to map an entity surface
form or entity mention (alternative label), to the canonical
entity name (i.e., label).</p>
        <p>We can formalize the entity linking task as the
following triplestore:
&lt;  ,  ,  &gt;,
(4)
where  ∈  the set of skill and occupation entities,
and  ∈  the set of skill and occupation mentions
(i.e., alternative labels for the ESCO skill and occupation
labels). Lastly,  ∈ , meaning that the predicate can be
either signalling that the mention is an alternative label
or not an alternative for the given ESCO entity.</p>
        <p>Given an entity,  and a mention , we are
interested in finding out what type of relation there exists
between  and . As such, we formalize the entity
linking as a masked language problem via  =
 [ ] .</p>
        <p>In Figure 1, the blue boxes represent two examples of
alternative labels for the occupation electron beam welder.</p>
        <p>We formalize the template for our second set of
prompts as:</p>
      </sec>
      <sec id="sec-1-8">
        <title>We formulate the verbalizer  such that:</title>
        <p>e [MASK] m
 =  → ,
(5)
Lastly, we formulate two diferent verbalizers  1 and  2  = {is an synonym for, it not a synonym for}
such that:
 1 = 1 →  1,
 2 = 2 →  2,
where 1={’Occupation’, ’Skill’} and the accompanying
label words  1 = {’occupation’, ’skill’}. Similarly, 2 =
{’isOptionalFor’, ’isEssentialFor’}, and the label words  2
= {’is optional for’, ’is essential for’}.</p>
        <p>Note that in our case, the verbalizers are one-to-one
mappings, whereas in the PTR methodology,
many-toone mappings are also supported. For the entity and</p>
      </sec>
      <sec id="sec-1-9">
        <title>For each generated example from the ESCO triple</title>
        <p>(2) stores, we also randomly sample negative examples by
(3) randomly shufling the objects and subject of the positive
triplestores and changing the predicate label to
noAlternativeLabel.
4.1.3. Question Answering</p>
      </sec>
      <sec id="sec-1-10">
        <title>For the QA task, we use so-called instructional templates</title>
        <p>as defined by Chung et al. [11] and Wei et al. [25].
Instructional templates prepend an instruction to the prompt.
 = {alternativeLabel, noAlternativeLabel}</p>
      </sec>
      <sec id="sec-1-11">
        <title>In our case, we prepend the example and question with</title>
        <p>"Answer the following with yes/no", instructing the PLM
how to answer the question that follows.</p>
        <p>The question and answering dataset is constructed
with the descriptions of the entities in ESCO. As such, 4.2.3. Experiment 3: Multitask Learning
we can construct a dataset as:
from the original training set and development set, and
evaluate the models on the original test set.</p>
        <p>We propose using  = {64, 128, 256} sets.
&lt; , {description} &gt;
(6)</p>
      </sec>
      <sec id="sec-1-12">
        <title>After having studied the efect of few-shot learning, we perform an ablation study to measure the efect of learning multiple tasks in parallel, i.e., transfer learning from one task to the other.</title>
        <p>We do so by fine-tuning the FLAN-T5 on all
combinations of tasks from a single to the full set, i.e., we train
FLAN-T5 on the RC+EC and consecutively on the EL and
QA tasks. We then test the performance of the
resulting model on all three data sets to identify whether, e.g.,
prompt tuning on EL can help performance on the QA
dataset.</p>
      </sec>
      <sec id="sec-1-13">
        <title>Next, we define the template  () as depicted in the</title>
        <p>example in Figure 2. Where we first prepend the
instruction "Q: Answer the following with yes/no" to the body
"Does [description] describe [entity label]", to finish it of
with "A: [MASK]".</p>
        <p>The verbalizer  then maps the {′′,′ ′} to the
label words {′′,′ ′}.</p>
        <p>We randomly sample correct examples, in addition to
generating negative examples by randomly sampling a
skill or occupation entity, and pairing this with a ran- 4.3. Implementation Details
domly sampled description from the set of available
descriptions, and tagging the label for the answer to be "no". Our model implementation relies on the HuggingFace,
This results in a balanced dataset, with a fifty-fifty split PyTorch and OpenPrompt frameworks (albeit with some
of positive and negative examples. customizations), proposed by Wolf et al. [27], Paszke et al.
[28] and Ding et al. [29] respectively.
4.2. Experiments For the zero-shot approach of the first experiment,
we turn to T5 and FLAN-T5, for which we use the
imIn order to answer our research questions, we propose plementation by the original authors [17, 25, 11]. More
the following experiments. specifically, we use the 3 billion parameter checkpoints
as found on huggingface under the names; ’t5-3b’, and</p>
        <sec id="sec-1-13-1">
          <title>4.2.1. Experiment 1: Zero-shot Learning ’google/flan-t5-xl’ .</title>
          <p>To answer our second research question we adjust
First, to better understand the labour market-specific the number of examples used for training the models by
tasks that we propose, we first test of-the-shelve PLMs comparing diferent values for parameter  (i.e., number
in a zero-shot setting, using our own generated prompt of samples). We optimize our PTR and Instruction-based
datasets for inference. ifnetuning models using AdamW, with a learning rate of</p>
          <p>In addition, to test the hypothesis that FLAN-T5’s mul- respectively 3 − 5 and 2 − 5. Furthermore, we reset
titask learning enables a better ability of learning addi- the weight decay on the normalization layers and bias.
tional (domain-specific) tasks, in our first experiment we We fine-tune all models using batch size 32, and train
directly compare of-the-shelve T5 and FLAN-T5 models, the PTR models for 10 epochs, whereas, we train the
on each of our three datasets. instruction based finetuning models for only 5. The best
model checkpoint is selected.
4.2.2. Experiment 2: K-shot Learning</p>
        </sec>
      </sec>
      <sec id="sec-1-14">
        <title>Next, having established the performance diferences</title>
        <p>between the of-the-shelve PLMs, we study the impact of
few-shot learning to steer the best performing PLM from
experiment 1 towards the domain-specific data and tasks,
where we perform an ablation study on the number of
examples () we use for few-shot learning.</p>
        <p>This is motivated by a.o., Han et al. [10], who report
comparable or even better results in the few-shot scenario
than e.g., methods that inject special symbols to index the
positions of entities and methods that inject both type
information and special symbols. The authors sample 
training instances and  validation instances per class</p>
        <sec id="sec-1-14-1">
          <title>4.4. Evaluation metrics</title>
          <p>In order to systematically evaluate few-shot performance,
we randomly pick K samples from the total dataset, and
use the remaining data to sample evaluation sets. This
sampling is done 9 times, each iteration we sample 512
random examples from the remaining data after the train/
test split. We report F1 scores averaged over 9 runs in
addition to standard deviations (± ). We argue that
sampling multiple splits gives a more robust measure of
the actual performance.</p>
          <p>Since the single EC+RC dataset contains two separate
tasks, it is important to avoid contamination between the
Model
train and test sets. Therefore, after the initial division,
we check all individual skill and occupation entities from
the train set, and remove all relations in the test set that
contain any of those entities. For the QA and EL training
data the risk of contamination is mitigated through the
train/test split (i.e., after the normal split unique entries
belong either to the train or test set).</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>5. Results</title>
      <sec id="sec-2-1">
        <title>In this section we present and summarize the results of our experiments described in Section 4.2.</title>
        <sec id="sec-2-1-1">
          <title>5.1. Experiment 1: Zero-shot learning</title>
        </sec>
      </sec>
      <sec id="sec-2-2">
        <title>The scaling of the model potentially gives us insights</title>
        <p>into how sample eficient the model is in learning the
behavior. Larger models are in-general more sample
eficient and as such require less examples to learn a
particular behavior [30].</p>
        <sec id="sec-2-2-1">
          <title>5.3. Experiment 3: Multitask learning</title>
        </sec>
      </sec>
      <sec id="sec-2-3">
        <title>Finally, we show the impact of learning single or mul</title>
        <p>tiple tasks at once. Results of our ablation experiments
are shown in Table 4, where we vary with models that
are trained on all combinations of diferent train sets of
prompts, which we evaluate on each of the three test set
of prompts.</p>
        <p>Here, we note that first, in some cases adding prompts
for additional tasks increases performance for the
original tasks, consider, e.g., the case for (testing on) EL, where
adding QA prompts yields an F1-score of 97.61 (row 4,
Table 4), and adding EC+RC prompts even gets performance
up to 98.48 (row 5, Table 4), whereas the model tuned
with EL prompts only, scores 95.17 F1 (row 3, Table 4).</p>
        <p>However, this does not apply for QA nor EC+RC,
where only tuning with respectively QA and EC+RC
prompts yields the highest score, nor for the case of
training on all additional prompts—these runs (bottom row in
Table 4) do not outperform the best performing models
tuned on one or two sets of prompts.</p>
        <p>Overall, this indicates that multitask learning can
contribute in some cases to increased performance.</p>
      </sec>
      <sec id="sec-2-4">
        <title>See Table 2 for the comparison of T5 and FLAN-T5 in</title>
        <p>0-shot learning, i.e., applied of the shelve for inference
on our generated prompts.</p>
        <p>First, we see that FLAN-T5 substantially outperforms
the non instruction-based finetuned counterpart T5 on
the QA (83.44 vs. 33.75 respectively) and EL tasks (57.38 5.3.1. Unseen task performance
vs. 33.89 respectively), but slightly underperforms on the
EC+RC tasks, at 44.54 for FLAN-T5 and 48.07 for the T5 Supporting these observations is the pattern around
permodel. formance on unseen tasks, i.e., models tuned on (a) task(s)</p>
        <p>A potential explanation for this might be the fact that that do not include the test task used for evaluation.
ConFLAN-T5 is trained on a variety of entity classification sider, e.g., EL; models that have not seen any EL prompts
tasks that do not involve skill and occupation entities (i.e., in their tuning stage, perform substantially worse with
the primary focus is on person and organisation entities). 58.96 for EC+RC and QA, 57.40 for EC+RC, and 60.31 for
As such, the learned patterns may interfere with the QA, versus between 95.17 and 98.48 for models that have
PLMs ability to recognize skills and occupations. seen EL prompts.</p>
        <p>Similar patterns are seen with the other tasks, where
5.2. Experiment 2: K-shot learning for EC+RC models that have not seen any EC+RC
prompts perform between 45.05–47.68, and around 50.55
In Table 3 we show the performance diferences at difer- and 51.60 for models that have. For QA, we see that
ent levels of  in the fewshot learning scenario. models without QA prompts in tuning score between</p>
        <p>First, we note how the performance of FLAN-T5 + 68.22–87.98, and models that have range from 93.24 to
PTR substantially outperforms both T5 and FLAN-T5 94.23.
from Table 2 with F1 scores between 50.42 and 51.60 However, increasing the number of tasks in tuning
across diefrent values of , compared to 48.07 and 44.54 does increase performance for unseen tasks in two out of
respectively for the zero-shot T5 and FLAN-T5. three cases: when testing on the EC+RC prompts, a model</p>
        <p>Next, we see that diferent values of  are optimal that combines QA and EL prompts in tuning scores 47.68,
for diferent tasks; with maximum scores at  = 128 and outperforms QA-only (45.93) and EL-only (45.04)
for EC+RC and QA at 51.60 and 94.23 respectively, and a models. Similarly, for QA, combining EC+RC and EL
maximum score of 98.06 for  = 256 for EL. prompts yields an F1-score of 87.98, whereas
EC+RConly yields 78.36, and EL-only a mere 68.22 F1.</p>
        <p>Model ↓/ →
FLAN-T5 + PTR
FLAN-T5 + Instruction tuning</p>
        <p>Train ↓ / Test → EC+RC QA EL sub-prompt finetuning a PLM on a mixture of task-specific
EC+RC 51.60± .47 78.36± .86 57.40± .16 datasets could increase the performance on labour market
QA 45.93± .26 94.23± .24 60.31± .12 specific benchmarks? , we performed experiment 2, where
EL 45.04± .26 68.22± .70 95.17± .39 we varied our  instruction samples for training our
EC+RC, QA 51.34± .23 93.24± .21 58.96± .52 best-performing PLM: FLAN-T5. Results demonstrated
EC+RC, EL 51.21± .45 87.98± .31 98.48± .29 that PTR-based finetuning with 128 examples leveraged
QA, EL 47.68± .23 93.69± .24 97.61± .14 the best performance. Overall, this yielded an 7.06%
perall 50.55± .70 94.10± .27 98.19± .32 formance increase over the zero-shot performance of
FLAN-T5. Additionally, further scaling of the number of
Table 4 examples, to 256, yielded only a 6.24% increase,
suggestF1 scores of our previously best performing model: FLAN-T5 ing no further performance increases for further scaling
with 128-shot learning, on the diferent combinations of tasks of the number of examples. Our results seem to indicate
we propose. that using PTR with labour market specific examples
yields improvements above and beyond the 1836 tasks</p>
        <p>FLAN-T5 was tuned on.</p>
        <p>Finally, models that are tuned on all tasks do not out- Lastly, we investigated the efects of transfer learning
perform models tuned on two tasks in two out of three across labour market specific tasks.
sets (only for QA does the full model perform better than Here, our results suggest that first, learning more tasks
models trained on two tasks). does yield increased performance on new, unseen tasks.
At the same time, the best-performing models often were
6. Discussion those that were trained on the evaluation task exclusively
(for EC+RC and QA). Overall, unsurprisingly, directly
Our paper explored three diferent questions. First, are learning the task at hand yields the best performing
mod"out-of-the-box" PLMs capable of generalizing learned be- els, but the fact that multiple tasks improve performance
havior to labour market specific applications? In order to for unseen tasks does suggest that the domain-specific
answer this question, we created three self-supervised knowledge that the PLMs receive in the tuning stage,
benchmarks from the ESCO taxonomy. do help solving the unseen task at hand. Prompt
tun</p>
        <p>To answer this question, we performed zero-shot com- ing on the QA and EL (i.e., instruction based finetuning)
paring between T5 and the instruction-tuned FLAN-T5, examples lead to a 3.14% improvement on the EC + RC
that has seen 1,836 additional tasks in prompts. Results task. Similarly, prompt tuning on the EC + RC and QA
showed that FLAN-T5 substantially outperforms T5 on examples yielded a 1.58% increase in performance on the
two labour market-specific tasks, with a 49.7% increase in EL task, with an overall 4.54% increase over the zero-shot
F1 score for QA, and 23.5% for EL. However in the EC+RC scenario. A possible explanation, "the ability to
recogtask where T5 outperforms FLAN-T5 by 3.53%. These nize whether an entity is an occupation or skill help
ifndings confirm that overall, the instruction-tuned FLAN discriminate whether two entities are not synonymous".
PLM benefits from having seen multiple tasks. The result However, training on all tasks did not seem to increase
for the EC+RC task can be explained by "misleading" the overall performance on any of the tasks. We believe
patterns learned from the more general finetuning on this is potentially caused by overlaps in learned behavior
named entity recognition (i.e., recognition of "Persons" from these diferent labour market specific tasks and the
and "Organizations", etc.). However, further investiga- 1836 tasks FLAN-T5 is already pre-trained on.
tions and ablation studies on general task tuning and its
exact influence on the performance is needed for a more 6.1. Implications
definite answer.</p>
        <p>On the second question, whether instruction and/or</p>
        <p>Finetuning PLMs is often an efective transfer mechanism
in NLP. However, an entire new model is often required
for every task. Our results indicate that cost-eficient
methods such as PTR and instruction-based finetuning
can significantly increase the performance of PLMs on
downstream labour market applications without
introducing any additional model layers, manual annotations,
and data augmentation.</p>
        <p>Furthermore, our results suggest that while training
on general tasks can increase the overall performance on
labour market specific applications, providing the general
models with labour market specific examples increases
performance above and beyond the general finetuning.</p>
        <sec id="sec-2-4-1">
          <title>6.2. Limitations</title>
        </sec>
      </sec>
      <sec id="sec-2-5">
        <title>There are several limitations to the current study that</title>
        <p>should be considered. First, we only used one-to-one
verbalizers between our classes and label words. Meaning
that every class label is mapped to one respective label
word. This would be a fruitful area for future research,
e.g., occupation can also be rewritten as job, or work.
Adding these alternatives to the label words will probably
yield improved performance over the current one-to-one
verbalizers.</p>
        <p>Second, for the purpose of this initial exploration we
focused primarily on binary classification tasks. As such,
we did not incorporate the possibility for a non-existing
relation in the PTR finetuning.</p>
        <p>Third, while the underlying methods support
multiple languages, we chose to conduct our experiments on
English. In part because the descriptions used in the QA
dataset are not complete for all 28 languages for which
ESCO is available. A future study could assess the
performance of PTR and instruction based finetuning without
examples in other languages.</p>
        <p>Lastly, this study primarily focused on the actual
isEssentialFor and isOptionalFor relations as they were
present in the ESCO taxonomy. As such, we did not
implement the reversed and or negative relations, even though
this was suggested to further increase performance.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>7. Conclusion</title>
      <p>In this study, we demonstrated that FLAN-T5
substantially outperforms T5 on the QA and EL tasks with
respectively 49.7% and 23.5% F1 scores. However, on the
remaining EC+RC task, T5 outperformed FLAN-T5 by
3.53%. Overall it seems that PLMs benefit from
instruction based finetuning even on labour market specific
benchmarks. However, if the task at hand is very
diferent from the task at hand, it can potentially hurt
performance, as demonstrated with the EC+RC tasks.</p>
      <p>Furthermore, our results seem to indicate that using
PTR with labour market specific examples yields
improvements above and beyond the 1,836 tasks FLAN-T5 was
tuned on. Unsurprisingly, directly learning the task at
hand leads to the best performing models. But, results
also show prompt tuning on other labour market specific
tasks can improve performance on unseen tasks. For
example, prompt tuning on EC+RC and QA improved
the performance on the EL task with 1.58%, and prompt
tuning on QA and EL improved the performance on the
EC+RC task by 3.14%.</p>
      <p>There are several limitations to the current study; i)
we solely used one-to-one verbalizer, ii) we focused
primarily on binary classification tasks, iii) we only focused
on English, and lastly we only used relations actually
present in the ESCO taxonomy, meaning that we did not
implement the reversed relations. Future studies could
address the limitations of this study by using
incrementing the amount of used label words, adding negative and
reversed relations, and using ESCO to construct parallel
datasets for all available languages.</p>
    </sec>
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