# Detecting Deceptive Behaviours through Facial Cues from Videos: A Systematic Review
## 4 Results of the SLR  
As depicted in Figure 2, during the identification phase (performed in May 2023), a total of 230 articles were retrieved using the two search engines: 203 from Scopus and 27 from WoS. As required by the duplication criterion, removing duplicate records resulted in 120 studies. By applying the understandability criterion, 6 studies that were not written in English were excluded, and therefore, a total of 114 articles were screened for the inclusion criteria. Moreover, the studies that did not satisfy the document type criterion (2 articles) and those that did not contain in the titles the terms used for the search (70 studies) were removed, and therefore, a total of 42 studies resulted at the end of the screening phase. Four studies that were not accessible in full text (availability criterion) and six studies that were considered not relevant for the focus of the review (relevance criterion) were removed. The relevance criterion to the abstract was also applied, and therefore, a total of 32 articles were retained for a full evaluation of eligibility, evaluated by two reviewers according to the quality evaluation checklist shown in Table 3. Seven studies with a score less than 1.5 were excluded, while the remaining twenty-four studies were included in the qualitative synthesis. Table 4 provides an overview of the selected studies. \begin{table}
\begin{tabular}{c c c} \hline \multicolumn{1}{c}{**Quality Assessment Questions**} & \multicolumn{1}{c}{**Scores**} \\ \hline \multirow{4}{*}{QA1} & Does the study describe the methods for video pre-processing? & 1—yes, the methods for video pre-processing are described in detail. & \\  & Does the study describe the methods for video & 0.5—partially, the methods for video pre-processing are summarised without providing details on the & \\  & pre-processing? & different steps. & 0—no, the methods for video pre-processing are only cited, without providing a description. & \\ \hline \multirow{4}{*}{QA2} & Does the study describe the facial extracted features? & 1—yes, the facial extracted features are described in detail. & \\  & Does the study describe the facial extracted features? & 0.5—partially, the facial extracted features are summarised without providing a detailed description. & \\  & Does the study describe the decision-making algorithm? & 1—yes, the decision-making algorithm is summarised without providing a detailed description. & \\  & Does the study use some & 0—no, the decision-making algorithm is not described. & \\ \hline \multirow{4}{*}{QA4} & Does the study use some & 1—yes, one or more datasets are used. & \\  & datasets for the evaluation & 0—no, datasets are not used. & \\ \cline{1-1}  & of the method? & & \\ \hline \end{tabular}
\end{table} 
Table 3: Quality evaluation checklist and scores. The selected studies were published mainly in conference proceedings (15 studies; 62.5%), followed by journals (9 studies; 37.5%). Figure 3 shows the temporal distribution of the selected studies, underlying the growing interest of the scientific community in the facial-deception-detection topic, which reached a peak in 2020.