8 THREATS TO VALIDITY
This section discusses threats related to validity.
Internal Validity: Internal validity is primarily jeop-
ardised by the possibility of errors in the implementa-
tion of the proposed and compared approaches in the
study. To reduce this risk, we build the proposed and
compared approaches on mature frameworks/libraries
(such as Jupyter and sklearn) and thoroughly test our
code and experiment scripts before and during the ex-
perimental study. Another risk may be posed by pa-
rameter settings for the investigated methods. How-
ever, for the learning models investigated in this pa-
per, we used default hyperparameters.
External Validity: External validity discusses the
generalizability of the results of this work. This work
uses only thirty-eight java projects, and their data is
gathered from the JIRA issue tracker. So, the results
of this work may not apply to projects developed in
different programming languages whose data is col-
lected from other issue trackers.
Construct Validity: Construct validity discusses the
performance measures used in this work. The pre-
sented work uses four performance measures: accu-
racy, precision, recall, and F1-score, for model evalu-
ation by ignoring the other important measures, which
may affect the results of this work. Although we
have verified with different works in the literature and
found that the measures used in this work are the most
popular measures for issue type prediction.
9 CONCLUSION
The issue-tracking systems are useful for software
maintenance activity. However, the incorrect clas-
sification of issues may create problems for high-
quality software applications. This problem re-
quires the manual intervention of researchers to ver-
ify developer-assigned issue types. An ample amount
of research has been done for issue-type prediction
over different datasets in the past. However, the used
datasets do not have manually verified issues. In this
work, we used the SmartSHARK release 2.2 dataset
containing manually verified projects for analysis and
handled various challenges related to the dataset men-
tioned above. Further, we proposed an ensemble-
based approach and evaluated its performance over
the 40302 manually validated issues of thirty-eight
java projects from the SmartSHARK data repository.
The results show that the proposed model performed
well when considering only the issue title as the in-
put. Further, we have compared the proposed ap-
proach with other models and found that the proposed
approach showed significant improvement compared
to the other models.
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