THE USE OF THE TECHNOLOGY ACCEPTANCE MODEL TO ANALYSE THE CLOUD-BASED PAYMENT SYSTEMS: A COMPREHENSIVE REVIEW OF THE LITERATURE

Over the past decades, organisations worldwide driven by the growth in e-commerce transactions have been investing in new payment methods in order to gradually align with the current trend of cashless transactions among individuals, businesses and governments. As a result, payments conducted over the internet or cloud-based payment systems (CBPS) have significantly increased. In this sense, the aim of this study is to provide a comprehensive review of studies that used the technology acceptance model (TAM) to analyse the CBPS. The findings of this study found 134 studies conducted between 2013 and 2020, which have applied the TAM. 118 new variables were tested alongside with the 5 basic constructs of TAM. Surveys are the preferred research method of data collection. Users have been the main focus of academics. China was the country with more studies conducted in CBPS using TAM as a research-based model, followed by India, Indonesia, Spain and Malaysia. Trust was the most used construct by academics to investigate the CBPS adoption, followed by perceived risk and perceived compatibility. SEM was the preferred research instrument for analysing the relationship among constructs followed by regression analysis and multi-group analysis. The majority of the studies on CBPS were conducted in one country. Only 5 cross-cultural studies, comparing different countries, were found. Tounekti, Ruiz-Martínez & Gomez (2019) conducted an online survey in 52 countries with 272 respondents. Lai (2018a) investigated the Association of Southeast Asian Nations (ASEAN) which is composed of eleven countries: Brunei, Cambodia, Timor-Leste, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand and Vietnam (Maizland & Albert 2020). William et al. (2017) surveyed 237 people from the Middle East and Africa. Guhr, Wiegard & Breitner (2013) conducted a survey with 270 consumers in 4 different countries (Finland, Germany, the USA and Japan). Finally, Hankun et al. (2016) investigated the differences and similarities between users in China and the USA.


INTRODUCTION
Over the past decades, the traditional payment systems have been impacted by the evolution of technology. The rise of new means of payments such as online banking, electronic wallets, mobile payments etc., have changed the way people buy and pay for goods and services received. As a result, several countries across the globe have become less dependent on cash payments, or in other words, cashless. Furthermore, the decline in cash usage to make payments could be also related to the emergence of the electronic commerce, or e-commerce, which has transformed the payment market. The adoption of e-commerce worldwide has changed the consumer's choice of payment as they have more options of electronic payments available (Mangiaracina & Perego 2009;Hampshire 2016;Yamaguti Mondego 2019).
Therefore, technology has been used as a mediator in commerce transactions and the development of new means of payment has been facilitating economic exchanges between businesses and consumers. Besides, the rise of the cloud computing has changed the way businesses are conducted.
Cloud computing, which refers to the method that allows individuals or organisations to store and access data over the Internet (Donoghue 2018), has been adopted as an effective basis for other technologies that work through networks to make improvements on their services and functions (Psannis, Batalla & Ishibashi 2020). The use of the cloud computing technology, for instance, is helping banks to have a competitive advantage in the market as it can provide reduction of costs, better profit margins, and simplify the maintenance and management of the application (Elhag 2015). Moreover, the widespread use of the Internet and mobile technology has been contributing to the evolution of the online banking and the digital payment systems (Alkhowaiter 2020).
Hence, payments conducted over the Internet, or cloud-based payment systems (CBPS), 'have been gaining momentum, enabling for the acceptance and processing of payments over the Internet rather than via physical devices' (Opus Consulting 2019).

LITERATURE REVIEW
Over the past years, researchers all over the world have been investigating the impact of new technologies on the adoption of new means of payment. These studies, which could be applied in several areas of knowledge, have investigated the reasons that could lead people to accept or reject a new payment system. In this context, several factors have been tested by academics, who have developed various research models, in order to provide 'a visual representation of theoretical constructs (and variables) of interest ' (Creswell 2009cited in Shuhaiber 2016. Notwithstanding many research models have been created, and different factors have been tested in the information technology field, the technology acceptance model (TAM) is the most frequently used research model pointed out by various authors Patil, Rana & Dwivedi 2018;Boteng & Sarpong 2019;Pal et al. 2019;Alkhowaiter 2020). The reason is due to the fact that TAM can predict the use of information technology and the determinants of acceptance (Kristensen 2016).
Proposed by Davis (1989), the TAM presents five constructs (external variables, perceived usefulness, perceived ease of use, attitude towards using and the actual system use) as it is depicted by Figure 1:  Hampshire 2016, p.66) According to Davis (1989), notwithstanding the behavioural intention to use a new technology is impacted by the external stimulus, the 'TAM is based upon two central constructs: perceived usefulness and perceived ease of use [which] reside within the cognitive response area of human psychology' (Hampshire 2016, p.11). Perceived usefulness (PU) is defined as 'the degree to which a person believes that using a particular system would enhance his or her job performance' (Davis 1989, p.320). In contrast, perceived ease of use (PEOU) refers to 'the degree to which a person believes that using a particular system would be free of effort. This follows the definition of "ease": freedom from difficulty or great effort' (Davis 1989, p.320).
It is noteworthy to point out that these external stimuli or external variables refer to the factors that could have impact on users' behaviour. Factors such as the features of the system, the development of processes and training could have an indirect impact on the adoption of a new technology as they have a direct impact on users' perceived usefulness and perceived ease of use (Duan 2012).
Thus, the 5 basic constructs of TAM (external variables, PU, PEOU, attitude and behavioural intention) can be used to explain the acceptance of new technologies. However, several academics have been adding new variables into TAM in order to test the influence of new constructs on the user's intention to adopt a new payment system. It is worth mentioning that the focus of these studies have presented a wide range of combinations and responses as it depends on the authors' approach to analyse different aspects of the users, merchants, banks and providers. Besides, the focus of the authors' studies has also been influenced by the evolution of the technology and the period in which the study was conducted.
In this context, this study has found 134 studies conducted between 2013 and 2020, which have applied the TAM. These studies are relating to all types of payments conducted over the Internet or CBPS (electronic payments, mobile payments, mobile banking, mobile wallet etc.). Table 1 shows the studies conducted in CBPS in the period analysed. It is important to mention that the analysis' acronyms are presented in Appendix 1.

Research Instrument and Focus
In the previous section, this paper has investigated previous studies conducted in the CBPS area, in which the TAM was applied. As a result, 134 studies conducted between 2013 and 2020 were found revealing that the preferred method of collecting data used by academics is questionnaire surveys. Interviews were conducted in 7 studies. Only two studies conducted in the period aforementioned had focus on both, surveys and interviews (Anthony & Mutalemwa 2014; Sidek 2015). Table 2 illustrates the focus of the studies: It is important to mention that in this literature review, this study divided the focus of 134 studies in three categories: Consumers, Merchant and Users. The main reason is that in many studies the authors have classified their subjects of study with different nomenclatures such as travelers, students, tourists and so forth. In this context, in order to organise, classify and provide a better understand of these distinct groups, this study has classified Consumers as people who pay the services provided, Merchants as organisations who supply the service to consumers and Users as people in general (all stakeholders: consumers, merchants, service providers etc).
Thus, according to the literature review, the majority of studies have focus on Users (81), followed by Consumers (50). It is worth mentioning that 1 study has focus on 'non-users'. Merchants were the focus of only 4 studies.

Countries analysed
In regards to the number of countries analysed by academics, this study found 37 different countries, which were analysed between 2013 and 2020. China was the country with more studies conducted in CBPS using TAM as a research-based model. 17 out of 134 studies were conducted in China. It was followed by India (14), Indonesia (13), Spain (13) and Malaysia (13). Table 3 shows the complete list of countries analysed during the aforementioned period: The majority of the studies on CBPS were conducted in one country. Only 5 cross-cultural studies, comparing different countries, were found. Tounekti, Ruiz-Martínez & Gomez (2019)

Influencing factors
As pointed out in the previous sections, this study have analysed 134 studies that have applied the technology acceptance model (TAM) during the period 2013-2020. Several authors have added or tested different factors with TAM in order to point out which factors have positive and negative impact on payments conducted over the Internet or CBPS (online banking, mobile banking, electronic payments, mobile payments, NFC payments, mobile wallet and so forth). It was found 118 new variables which were tested alongside with the 5 TAM constructs. Table 3 shows the different factors tested with TAM constructs: By far trust, which can be described as the perception that individuals need to rely on another person's intentions and motives (Shuhaiber 2016;Mondego, Gide & Chaudhry 2018), was the most used construct by academics to investigate the CBPS adoption. Trust appears in 71 studies conducted between 2013 and 2020. It was followed by perceived risk (44 studies It is worth mentioning that all the other factors presented in the papers analysed, despite having appearing less than the other factors listed above, by no means are less important. It only reflects academics' viewpoint and has to be taken into consideration as it sheds some light into the factors that have a positive and negative impact on CBPS adoption.

Techniques employed to analyse data
In relation to the research instruments used by academics to analyse data from stakeholders, this study found a wide variety of techniques employed by researchers as shown in Table 5. The complete list of acronyms is presented in Appendix 1.

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The Use of the Technology Acceptance Model to Analyse the Cloud-Based Payment Systems: ...   Agyei et al. 2020)

SUMMARY AND CONCLUSION
This paper has provided a scoping review of the literature of studies that have applied the TAM to investigate the factors that have a positive or negative influence on CBPS adoption during the period 2013-2020.
The findings of 134 papers, published during the aforementioned period, suggest that the majority of the studies conducted questionnaire surveys as the main instrument of collecting data from participants and users were the main focus of academics. Few studies have gathering information from participants through interviews, as well as few papers take into account the point of view of merchants.
China was the country with more studies conducted in CBPS using TAM as a research-based model. It was followed by India, Indonesia, Spain and Malaysia. Notwithstanding the number of studies have increased in some countries (e.g India and Indonesia) during the period analysed, it is noticeable that the number of studies conducted in some countries seems under-represented and in others there is no data available. Besides, only 5 studies were found, which have investigated crosscultural similarities and differences.
Trust was the most used construct by academics to investigate the CBPS adoption, followed by perceived risk, perceived compatibility, perceived security levels and subjective norms.
Finally, many studies used the fit index to evaluate the fitness of the model and SEM was the preferred research instrument for analysing the relationship among constructs, followed by regression analysis and multi-group analysis.

Limitations and Future research opportunities
This paper has summarised studies conducted and published between 2013 and 2020. The reason to focus on the aforementioned period was that the consumers' choices of payment methods have significantly increased over the past years, due to the emergence of e-commerce and the rapid advancement of technology. Besides, the main focus of this study was to analyse recent studies conducted in the CBPS area, which has used TAM as a research-based model, and point out future research opportunities.

RA -Regression Analysis
TA -Thematic Analysis