opinion term(s) while detecting the sentiment po-
larity towards a named entity; (ii) while the other
approach uses a convolutional neural network (dos
Santos and Gatti,2014) supplemented with some
pre-defined heuristic rules. We compare the ef-
fectiveness of both approaches through extensive
experiments and discuss our findings to provide
valuable insights for future developments of ELSA
models for real world commercial scenarios.
2 Related Work
Since the entity-level sentiment analysis task is
closely related to aspect-level sentiment analysis, in
this section, we first briefly review the aspect-level
sentiment analysis task followed by the entity-level
sentiment analysis task in order to clarify the dis-
tinction between these two tasks while discussing
our rationale behind developing an entity-level sen-
timent analysis model for contact centers.
2.1 Aspect-Based Sentiment Analysis (ABSA)
ABSA aims to classify the sentiment polarity of
aspects of certain objects. Many previous studies
are focused on this research (Sun et al.,2019;Tang
et al.,2016;He et al.,2018;Zhao et al.,2020;Zhou
et al.,2019). A more fine-grained related task is
aspect sentiment triplet extraction (ASTE) (Peng
et al.,2020;Xu et al.,2020), which extracts a triplet
– aspect term, opinion term and sentiment – from
the input. Detection of aspects in both ABSA or
ASTE often relies on implicit lexical or semantic
signs, for instance, the food is too spicy suggests
that this comment is about the taste aspect. This
is different from the entity recognition task where
the goal is to detect the named entities in a given
utterance based on the overall context.
2.2 Entity-level Sentiment Analysis (ELSA)
ELSA aims to predict the sentiment of named enti-
ties in a given text input (Steinberger et al.,2011;
Saif et al.,2014). These named entities are usu-
ally application dependent. One recent work on
ELSA is the work of Luo and Mu (2022), where
they studied entity sentiment in news documents.
Another prominent work on ELSA is the work of
Ding et al. (2018), where an entity-level sentiment
analysis tool was proposed for Github issue com-
ments. Contrary to the above studies that focused
on typed text, our focus is on noisy textual data
(i.e., speech transcripts). Moreover, our proposed
models can infer both entity sentiment and corre-
sponding opinion terms for a better analysis of user
sentiments towards products or companies in busi-
ness telephone conversations in contact centers.
3 Task Description
Let us assume that we have an utterance
U=
w1, w2, ..., wn
containing
n
words. The goal of
the ELSA task is to identify
m
opinion words
OW=ow1, ow2, ..., owm
, (where
m
<
n
), and
classify the sentiment of the identified opinion
words towards the target entity
e
in the given utter-
ance. In Table 1, we show some examples of the
ELSA task to detect user sentiments towards prod-
ucts and organization type entities. In the first two
examples, the customer is directly expressing posi-
tive sentiment about the named entity. For instance,
(i) they say “I love it” indicating “Google” in con-
text, or (ii) they are “very impressed” with “MAC”.
In the third and fourth examples, customers are
expressing negative sentiment about a product or
facet associated with the company, e.g., “He has
a hard time finding a good yogurt from Walmart”
is a comment about the quality of Walmart’s ser-
vice, not a comment about yogurt. Similarly, in the
fourth example, difficulty navigating the Instacart
app is indirectly an indication of negative sentiment
concerning Instacart.
4 Dataset Construction
As noted earlier, there is no publicly available
dataset for the ELSA task. We therefore had to
create and annotate our own dataset. The first ma-
jor issue that we observed while constructing a
dataset for ELSA is that the entity-level sentiment
events in our telephone transcripts are very infre-
quent. Hence, random data sampling techniques
might yield an imbalanced dataset where most ut-
terances would not have any positive or negative
sentiments towards an entity. We therefore used
two pre-existing models — a named entity recog-
nition (NER) model based on DistilBERT (Sanh
et al.,2019) that was trained to identify
Organiza-
tion
and
Product
type entities and a convolutional
neural network (CNN) (Krizhevsky et al.,2012;
dos Santos and Gatti,2014;Albawi et al.,2017)
sentiment analysis model — to sample 13000 ut-
terances that contained at least one named entity
and one positive or negative sentiment predicted
by these models. To balance the dataset, we sam-
pled an additional 10000 utterances containing at
least one entity and having no polarized sentiments