1 INTRODUCTION Rational of the research In the context of global economic integration and profound influence of information technology (IT) in all aspects of life and socio-economy, besides opportunities and advantages of globalization, Vietnamese enterprises will face many challenges and difficulties that may affect objectives and operational strategies The process of achieving business objectives of enterprises is affected by the accounting function In order to fully and effectively perform these functions, the accounting information system (AIS) plays an important role AIS will help businesses successfully implement core business objectives and strategies by providing useful information to managers to plan and control their business and support immediately for managers to make management decisions (Soudani, 2012) The AIS support the managerial and processes making decision of the manager (Gelinas et al, 2011) Therefore, it is possible to see the role and essential of AIS in business, quality of AIS will benefit the business in the operation and provide useful information The AIS is a complex structure combined of many techniques and people, in which human beings are system users (Turban et al, 2008) Employees use system via affecting the technology, equipment and processes throughout the work process The process of using system of employees will contribute to improving the efficiency of the system such as solving problems faster and providing more timely information, contributing to the development of the business value, to achieve the goal of the enterprise, for example, the use of AIS in the ERP environment will provide information to support management in decision making and control, which requires very high on the accounting system and ERP is an opportunity for accountants to perform this function (Romney & Steinbart, 2015) The success of AIS is influenced by process interaction and system users by themselves, thus showing the important role of using AIS in the enterprise, especially the ERP is a complex and integrated of AIS and other information system (IS) in the enterprise, so the behaviour use of AIS is more important and meaningful According to DeLone & McLean (2016), system quality will affect the behavior of system use of employees and thereby contribute positively to the benefits that the system achieves The process of using the system of employees is the basis for enterprises to evaluate the results of their work, to improve the use of AIS on the one hand to contribute to the interests of enterprises in improving operational efficiency, on the one hand, affect the users themselves helps them feel confident and improve the quality of their work In recent years, there have been many researches that explain the use of IS based TAM or the incorporation of TAM and success IS model, including Wixom & Todd (2005), the Saeed & AbdinnourHelm (2008) have formed a model that combines the success IS model and TAM, which has been widely used The study by Uzoka et al (2008) has considered the application of ERP system to understand and evaluate main factors that influence to decision to apply and use ERP in the enterprise Additionally, there are a number of studies assessing the impact of factors such as organizational support, personal characteristics, characteristics of technology, quality of output information, subjective standards of behavior use of ERP such as Calisir et al (2009); Zhang et al (2013); Rajan & Baral (2015); Lee et al (2010) These studies were conducted in different countries in the world; it shows the studies using IS are importance and topicality in the current background However, these studies have just focused on a number of factors affect the using ERP systems, not to mention a AIS in detail, and in Vietnam, research factors affecting behavior using AIS has not been implemented Thus, in the scope of the survey and the author's research, many studies have been related to AIS, but almost no research fully, comprehensive behavioral use of AIS and considers the factors that affect the use of AIS Starting from the research context, the project "Factors affecting the use of Accounting Information System in the environment of enterprise resource planning system in enterprises in Vietnam", which author selects, is Ph.D thesis Research Objective The main objective of the research is test how the factors affect the use of AIS in Vietnamese enterprises From the above point of view, the consideration of the factors affecting the use of AIS is a combination of various research concepts in relevant models and theories leading to the use of AIS include: - Testing of the impact directly of perceived usefulness and perceived ease of use of AIS on the use of AIS - Testing the direct impact of the quality of AIS on the use of AIS - Testing the direct impact of organizational support on the use of AIS - Testing the mediating role of the perceived usefulness on the relationship between the quality of AIS and the use of AIS - Testing the mediating role of perceived usefulness on the relationship between organizational support and the use of AIS Research subjects, respondents and research scope 3.1 Research subjects: The research subjects of the thesis are factors influencing the use of AIS in the ERP environment in Vietnamese enterprises 3.2 Respondents: In order to achieve the above mentioned research objectives, the surveyed subjects is selected are employees involved in use directly and managers in the ERP environment at Vietnamese enterprises 3.3 Research scope: Surveys and data collection were conducted at Vietnamese enterprises, limited to Ho Chi Minh City (HCMC) and some neighboring provinces, but mainly in Ho Chi Minh City The surveyed enterprises in this study are those who are implementing ERP systems in management, survey enterprises of various types, sizes and sectors (excluding financial institutions) Research Methodology With the goal of testing scientific theories and evaluation of reseach definitions in specific environment in Vietnam, to implement the project and achieve research objectives, the authors have used methods quantitative research includes stages: preliminary qualitative research and formal quantitative research Significance of the study  Scientific significance - To systematically and affirm the relationship between research definitions in the theories related to the behavior of using IS - Reinforce empirical evidence for the application TAM, success IS theory and organizational support theory in research using of AIS in the ERP environment - Provide additional empirical evidence shows that the use of scales related to the AIS in a developing country like Vietnam is reasonable 3  Practical significance - Making clearly about the use of AIS as well as relationships among factors with use of AIS in the context of the application of IT in accounting did change the way to handle accounting works - The study results also contribute in terms of practical help for businesses can identify and control the factors that affect the behavior using AIS, help businesses in forecasting and improved using of AIS of the staff, contribute to improving the efficiency of application deployment and use of AIS of ERP in the enterprise - The research results about using of AIS is the reference value for researchers, lecturers and students in the field both accounting and business administration in Vietnam Besides, the research results will also be an important content should be added in the teaching material of AIS course, particularly studies of behavior using of AIS of staff, helps for decision makers, researchers, teaching accounting program development, training content related AIS more consistent and better quality, to be able to keep up with the level of the countries in the region and on the world Struture of the research Besides the introduction, the structure of the research consists of chapters, including: Introduction presents the content about why author selects this subject, research objectives, objects, scope of research, respondents, research methods, significance of the research The main content of the thesis is composed of chapters with the following basic contents: Chapter 1: Overview of research related to thesis, this chapter introduces an overview of the research situation in the world and Vietnam, related to this thesis, through which the author draws comments on these studies and identify research gaps Chapter 2: The literature review, this chapter presents the concepts and issues related to IS, AIS and ERP system Also, this chapter demonstrates theoretical background, the definitions used in the research Chapter 3: Research methodology, presentation on research process, research framework, research hypotheses and research methods applied in the thesis Chapter 4: Research results of research and discussion, presenting survey results on factors influencing the use of AIS in Vietnamese enterprises In this chapter, author presents research results of the second stage of quantitative research is preliminary qualitative research and formal quantitative research, shows analytical techniques for measuring the scale, evaluates research model, validates research hypotheses, and analyzes the mediating role of research variables, compares with previous published studies for evaluation, analysis and discussion Chapter 5: Conclusions and research implication, this section presents a summary and assessment of the contents was finished, as well as offering the implications research, recommendations for improvement In addition, this chapter also presents the limitations of the thesis and future research The last part of the thesis is the scientific works related to the thesis, references and appendices 4 Chapter 1: Overview of researches related to thesis Summing up of domestic and foreign studies related to thesis is a key part of any research The process of reviewing the research will show how the situation research about problems in not only the world but also Vietnam relates to the research problem of the subject As stated, the author's study is to test scientific theories based on available background theories, it is possible that relevant studies have been conducted but with different perspectives and perspectives in different environments and conditions Reviewing the research is important in the research topic orientation of the author so as not to duplicate the research has done but still have certain scientific and practical significance In addition, the review summarizes researches has been done, analyzes the strengths and limitations of the research and identifies the research gap With the above reasons, the reviews of author’s research are classified into two areas in the country and abroad For researchers in abroad, authors classified into two main research directions include: (1) the studies related to the use of IS and ERP, (2) the studies related to using AIS For studies in Vietnam, the author also classified into two main research directions include: (1) the studies related to IS and ERP, (2) research related to AIS 1.1 Researches abroad 1.1.1 The studies related to the use of IS and ERP: Currently, according to the author’s understanding, there are a number of studies related to the use of IS and assessment factors used IS performance or benefits companies, the IS in these studies are IS that it considered in different contexts in detail, including: Baroudi et al (1986), Torkzadeh & Dwyer (1994), Gelderman (1998), Bajaj & Nidumolu (1998), Saeed & Abdinnour-Helm (2008) The research by Wixom & Todd (2005) related to the construction of integrated model of research behavioral using IS, the author has combined IS success model and TAM in research factors affecting use of IS Research on successful IS model, sample size, scale and relationship (Petter et al, 2008) The author of this study was applied the theory of Reasoned Action and the theory of Planned Behavior of Fishbein & Ajzen explain why some of the IS is ready to be accepted by users the other systems Research by Dulcic et al (2012) on the use of Decision Support System (DSS) in business units in Croatia With the adoption TAM in this study, it has been shown that importance of perceived usefulness and perceived ease of use are core factors that affect perception of using DSS, both of these features are positively related to behavioral intentions using DSS and use DSS According to the author's summary about worldwide studies, there are quite a number of studies related to the application of TAM and the IS success model in identifying factors that influence behavior of using the ERP system Especially, researches by Amoako-Gyampah & Salam (2004); Uzoka et al (2008), Calisir et al (2009) With the aim of studying of factors influencing the intention to use ERP, Lee et al (2010) also applied the TAM to implement and achieve the results Research of Ling Keong (2012) relating to the interpretation intend to use ERP with application model UTAUT (Unified theory of acceptance and use of technology) and TAM Research by Zhang et al (2013) examined the impact of three factors including: organizational support, subjective criteria and the quality of information output to using ERP Study of Rajan & Baral (2015) about factors influencing the use of ERP and the impact to the last user Research uses the TAM and finds effects of a number of individual, organizational and technological factors on using ERP system and its impact on the last user 5 1.1.2 Researches involved using Accounting Information System: According to author's review of worldwide research, there are some studies related to the use of AIS in the business, namely: the study of Mndzebele (2013) research examines impacts of using AIS in enterprises, the impact of use of AIS on effectiveness of e-commerce in the company of Spremic & Jakovic (2012) In addition, there are a number of studies assessing impact of using AIS on cost management, saving time and reducing operating costs (Ponisciakova & Partners, 2015) Research on the impact of external factors on the use of AIS, including the study by Abduljalil & Zainuddin (2015); Ramli (2013) on the impact of external factors on the use of AIS 1.2 Researches in Viet Nam: For research in Vietnam, there are quite a number of studies on AIS in different aspects, the authors synthesize and classify into the following research directions: 1.2.1 Researches related to AIS: For this research, includes studies related to the organization of AIS, developing of AIS, evaluation of the quality of AIS and factors affecting the quality of AIS, and some researches on the use of AIS  General researches of AIS: For the study of the organization of AIS, a number of studies by Pham Tra Lam (2012) and Nguyen Thi Phuong Thao (2014) have been conducted Regarding the research on quality evaluation, the effectiveness of AIS includes studies by Huynh Thi Kim Ngoc (2013); Dao Ngoc Hanh (2014); Le Thi Ni (2014); Nguyen Huu Binh (2014) These research directions have in common study of factors affecting the effectiveness, efficiency and quality of AIS in small and medium enterprises in Ho Chi Minh City, given solutions to improve the quality of AIS in small and medium enterprises  General researches on the use of AIS: These research directions include the following research: Pham My Nhut (2017) was carried out with the following objectives: (1) to determine the satisfaction of the users of AIS and factors affecting the satisfaction of users of AIS; (2) determine the impact of influencing factors; (3) assess differences in the level of impact of factors affecting user satisfaction by occupation, experience and educational level The research by Vo Thi Hieu (2017) is based on the theory of resources with purpose of studying impact of customer orientation, orienting competitors to the level of using management accounting information to improve business results in Vietnam enterprises 1.2.2 Researches involved in IS and ERP In Vietnam, there are also a number of studies published by authors in the journal of scientific research to consider factors that affect successful implementation of ERP: - The study by Nguy Thi Hien & Pham Quoc Trung (2013) on factors affecting successful implementation of ERP in Vietnam This study explores the factors influencing success of ERP in Vietnam - Content of research on factors influencing successful implementation of ERP in Vietnam also has some authors, such as research by Nguyen Huu Hoang Tho (2012), Tran Duc Quy (2015) and Ngo Duy Hinh (2013, Le Thi Kim Thoa (2011), Tran Thi Hong Oanh (2015), Nguyen Thi Hong Yen (2016) The objective of studies is to identify and consider the key factors for successful implementation of ERP in Vietnam 6 - Research on the impact of ERP application on AIS, on internal control or impact on accounting benefits, such as research by Tran Thanh Thuy (2011), Lu Thi Kim Phung 2012), Phan Thi Thu Hien (2015), Tran Thi Thu Hien (2016) - Recently, the study by Nguyen Phuoc Bao An et al (2016) related to the factors influencing the decision to use ERP software is a combination of TAM and IS success model 1.3 Identification of research gap: Over the scope of the author's research in Vietnam and abroad, it is clear that the problem of research AIS has been very popular and neccessary Authors have made comments and views on the quality of AIS and most of these studies related to the identification of factors affecting quality of AIS and the role of quality of AIS in terms of performance in business These studies use only quality elements of IS in IS success model to learn and evaluate quality of IS, assess the satisfaction of users of IS, not care; consider the problem of behavior using AIS Thus, the research gap in this topic is the study of the factors affecting the use of AIS in Vietnamese enterprises Chapter 2: Literature Review Chapter summarized research related to the thesis both in not only in Vietnam but also abroad, summarizing the research associated with the research objective that the topic is addressed By evaluating relevant studies, the author identifies the research gap and the neccessary for research For any study, the most important issue is the foundation of theoretical foundations, particularly the types of scientifically validated theories Therefore, the goal should be achieved in this chapter is to introduce the theoretical basis and theoretical background related to the construction of model and hypotheses Specifically, first presented the theoretical bases of IS, AIS and ERP, followed by the presentation of the theoretical background support for modeling and imitation research theories including: TAM, successful IS model, organizational support theory Based on background theories, the author argues and presents the definitions used in this subject related to the AIS 2.1 Introduce about information system and accounting information system: 2.1.1 Information system (IS): IS are systems that help generate information for the user, a tool used by managers to carry out analysis and decision-making related to economic activities (McLeod & Schell, 2007) The main objective of IS in organizationl is to make organization effective and efficient (Bagranoff, 2010) According to O'Brien & Maracas (2011), IS are understood to be an organized combination of people, hardware, software, communications networks, data sources, policies and procedures, to carry out the collection, storage, conversion of data into information and communication of information within an organization Therefore, the IS is a collection of many parts and components in a relationship with the goal of converting data into useful information 2.1.2 Accounting information system (AIS): In terms of the overall relationship with the whole organization, AIS is a component of the organization, a special subsystem of enterprise IS, a unified structure in the organization of the use of physical and other components to convert economic data into accounting information are intended to satisfy the information needs of many different users to make decision The AIS is designed to transfer data into useful accounting reports and present these reports to internal managers and external agents Therefore, The AIS also has characteristics and components of IS According to Susanto (2013), AIS is an essential integration of a variety of business processing systems, the integration of subsystems, link components, harmoniously combined to process financial data into accounting information Under this understanding, AIS will carry out activities such as collecting, recording input data, storing and processing data to generate information, providing output to the decision maker (Romney & Steinbart, 2015) Moreover, the AIS is considered as a special subsystem of management IS, so it fully have the characteristics of a IS (Gelinas et al, 2011) 2.2 Enterprises Resource Planning (ERP) According to the author's research, there are several ERP definitions by Umble & Umble (2002); Hwa Chung & Snyder (2000); Dredden & Bergdolt (2007); Yang & Su (2009) There are many different definitions about ERP, however, it is understandable that ERP is a IS, in which integrates all aspects of an organization's operations into one database, processed by computer software and implementation process automation to help manage critical operations efficiently and effectively 2.3 Some background theories used in the research: 2.3.1 Technology Acceptance Model (TAM) The issue of adopting technology plays a vital role, especially in applying IT in management In the 70s of the last century, the demand for technology began to develop rapidly, accompanied by the failure of technology application, creating the demand research about IS Adapted from the model of rationed action theory (Fishbein & Ajzen, 1975), TAM model is used to explain and predict the acceptance and use of technology The TAM has been extensively tested and accepted in IT research, which is considered to be a good predictive model In particular, the intention to use has a significant correlation to its use, where intention is important to its use, and other factors affect its use indirectly through intent use (Davis, 1989) Perceived usefulness Perceived ease of use Attitude toward Usage Intention to use Actual usage Figure 2.3 TAM model (Davis, 1989) As suggested by Davis, the motivation of user is described by relationship of three factors: perceived ease of use, perceived usefulness, and attitude used The TAM model has been widely applied and developed This model has become popular, cited in many studies on the use of IS In the field of IS, researchers have widely used the TAM model to study the application of different technologies and TAM has become the most influential theory in the field of IS Researchers have also expanded TAM (Wixom & Todd, 2005) and research findings suggest that perceived usefulness is positively related to use system According to the TAM, perceived usefulness is also affected by perceived ease of use because the system easier to use as it will be more useful and people feel easy to use, it will be more confident in using the system 8 Perceived usefulness External variables (personality traits, system characteristics, demographics) Perceived ease of use Actual usage Intention to use Attitude toward usage Figure 2.4: The extension of TAM model (Wixom & Todd, 2005) As mentioned, the TAM model was developed by Fred Davis based on rationed action theory of Fishbein & Ajzen (1975) In the theoretical model of Fishbein and Ajzen, the authors argue that the true behavior of a human being can be determined by examining his or her earlier intentions with the belief that the person will have certain behavior The belief is that perceived usefulness and perceived ease of use 2.3.2 Information system success model A successful IS is a research literature that provides a comprehensive understanding about the success of IS by identifying, describing, and explaining the relationships among the most important elements of success along with the type of IS being evaluated The initial development of this theory was made by DeLone & McLean and was updated by the leading authors later Nowadays, the IS success model is cited in numerous articles of scientific research, and is considered as the most influential theory in the IS research Information quality Intension to use Use System quality Net impacts User satisfaction Service quality Figure 2.7 Upgrading model of IS success (DeLone & McLean, 2016) The variables in the IS success model of DeLone & McLean (2016) included: - System quality: The desirable properties of IS, such as ease of use, flexibility, reliability, easy to learn, time to meet the requirements, sophistication - Information quality: The desired characteristics of the output information such as rationality, reliability, comprehensiveness, completeness, consistency, usefulness and efficiency - Service quality: Quality of the support services that users receive from the IT department in the organization - Using the system: The level and manner in which employees and customers use the capabilities of a IS For example: number of uses, frequency of use, nature of use, appropriateness of use, level of use and purpose of use 9 - User Satisfaction: The level of user satisfaction and satisfaction with system and support activities of the system - Net impacts: The extent to which the IS contributes (or not contribute) to the success of the individual, group, enterprise, sector or society For example: improve decision-making, improve productivity, increase revenue, reduce costs, and improve profitability, market efficiency, consumer welfare, job creation, and economic development 2.3.3 Organizational support theory: Organizational support is arguably an important success factor for improving the performance of any organization as well as the success of adopting the new system (Lee et al, 2006) Organizational Support Theory (Eisenberger et al, 1986) identifies organizational readiness to reward increased work and social needs, and enhances trust related to organizational values, organizational assessment through employee contributions and interest in the welfare of employees Awareness of assisting supportive organizations will be available from the organization when needed to carry out work and to face with stressful situations Organizational support to consider factors that increase employees’ satisfaction and evaluate performance appraisals of increased work effort through their contributions (Rhoades & Eisenberger, 2002), organizational support recognition as an important value for improvement employee quality, morale and job satisfaction as well as business performance (Lee et al, 2010) 2.4 Research definitions used in the subject: In the research, the author uses the following research definitions: - Quality of AIS - Organizational support - Perceived usefulness of AIS - Perceived the ease of use of AIS - Use of AIS Using the meaning of using the IS in the IS success model of DeLone & McLean (2016), the author identifies the use of AIS including the following aspects:  Required level: This is the basic level of use of AIS with the process and determines substance of interaction with the user in the process Using system in this case is mandatory when most of processing processes established by the system work, so the system user is to support the process, showing the interaction between the work system and the AIS  Level of use of system features: In this respect, the measurement of the use of system features by the user in the system work An AIS has many different functions in the work process, people will use the specific features of the system during the work  Frequency of use: This aspect measures the number of times the functions of AIS are used compared to the total time that the system functions can be used in the processing In a detailed processing process, this aspect evaluates the frequency of system use, this aspect of which often occurs at user level of AIS  The thoroughness of use: the use of AIS requires careful consideration during the work, the thoroughness of the accountant in the work will affect quality of work output results, thereby contributing to quality of AIS The author learns use of AIS in this study and the factors that influence the use of AIS to explain the use of AIS in the Vietnamese enterprises 10 Chapter 3: Research Methodology To achieve the research objectives for the subject, the next important issue is the research methodology; this chapter focuses on presente research methods Specifically: - First, the author presents the research process, research model and research hypothesis - Second, the scales of research definitions used in the research mode, the research model has seven scales including: quality of AIS (ASQ), training and education (TRE), work environment (WE), communication (CO), perceived usefulness of AIS (PU), perceived ease of use of AIS (PEU), use of AIS (ASU) - Third, presenting the research methodology used is a two-stage quantitative approach that is a preliminary study and a formal study At each stage, the author clarifies research objectives, methodology and research content, data processing tools 3.1 Research process: The research process is based on the general process of research methodology in scientific theoretical examination (Nguyen Dinh Tho, 2013) Specifically: Related research review Literature background - IS - AIS - ERP system - IS success theory - TAM - Organizational support theory Research model Research problem Factors affecting the use of AIS in the environment of ERP system in enterprises in Vietnam Preliminary research - Evaluating scale with Cronbach’s Alpha - EFA analysis Draft scale Adjusted Formal research (Formal scale) Measurement model - Evaluating scale with Cronbach’s Alpha - EFA analysis - CFA analysis Structural modeling and hypothesis testing CB-SEM Research results and disscussion Figure 3.2 Research process (Nguyen Dinh Tho, 2013) 3.2 Research model and Research hypotheses: The research model is based on relevant theories, namely: For the TAM, the author uses relationship among external variables that affect the perceived usefulness and the perceived ease of use of AIS Variable perceived usefulness and perceived ease of use AIS is considered beliefs about behavior that employees will use the system, when there is faith in action will have an impact on attitudes and use of AIS 11 For IS success theory, the author applies the relationship between the quality of IS and the use of IS to examine the relationship between the quality of AIS and using AIS In the IS success model, there are three elements, including the quality of IS, the quality of information and the quality of service affecting the use of IS However, when considered in AIS, the author sees the quality of AIS as the most important because of the quality AIS will create the quality of accounting information, in general, the use of IS may require the quality of information from other departments to promote usage behavior, the use of AIS may also need information from the department or other systems provide, but from the author's point of view the accuountant direct use AIS is important first to realize quality from AIS The quality of AIS is the basis for the employee to see if they have confidence in the objects they will use, from the beliefs they have about the object they will use that will promote confidence in their use and will affect their usage behavior For organizational support theory, the author uses three specific definitions of organizational support from this theory: training, communication and work environment, in theory, the group of factors can affect perceived usefulness and perceived ease of use of AIS, and thus will affect the behavior using AIS These theories are the basis for understanding the quality of AIS, understanding the organizational support factor as well as analyzing these factors affecting the behavior of using AIS The research model is as follows: Quality of AIS H1 H3 Training and education Perceived usefulness of AIS H9 H2 H5 H11 H4 Use of AIS H7 Work environment H6 Perceived ease to use of AIS H10 H8 Communication Figure 3.3 Research model (Source: synthesis of the author) In the above model, there are latent variables: 3.3 - Quality of AIS - Training and education - Work environment - Communication - Perceived usefulness of AIS - Perceived ease to use of AIS - Use of AIS Research design and research methodology As stated, the purpose of this study is to test the scientific theory To this, the author uses a quantitative approach based on inference (from theory to research) (Nguyen Dinh Tho, 2013) through two phases: preliminary research and formal research 12 3.3.1 Preliminary research 3.3.1.1 Objective of preliminary research Preliminary research was carried out to informal assess of the scale, test the reliability and values construct of the research concepts in the research model including the quality of AIS, training and education, work environment, communication, perceived usefulness of AIS, perceived ease to use of AIS and the use of AIS 3.3.1.2 Methods and contents of preliminary research The method used in the preliminary study is the survey method - Data collection tool in preliminary research: A detailed questionnaire, questionnaire with full questions measuring research concepts, and stimulation of responders' responses The author conducts direct and indirect surveys of individuals directly using the AIS and individuals involved in the use of AIS in the ERP system - Sample size: Determining sample size depends on many factors such as data processing techniques, reliability; sample size is as large as possible but waste time and cost As a result, researchers often determine the sample size needed through empirical formulas In the preliminary study, two data processing techniques were used: Cronbach's Alpha coefficient analysis and EFA analysis According to Nguyen Dinh Tho (2013), to use EFA requires large sample size; the sample size is usually based on the minimum size and the number of observed variables included in the analysis The good sample size is 100 and the observation ratio on the measurement variable is 5:1, if the best is 10:1 or higher In this preliminary study, the author chooses a minimum sample size of 100 to ensure that the analysis results are reliable - Selection of sampling Method: In this preliminary study, the author selected a non-probability sampling method, namely the convenient sampling technique and sprout development 3.3.1.3 Data processing tools The data processing tool used in the preliminary study consisted of two data analysis techniques, which analyzed the reliability of the scale using the Cronbach's Alpha coefficient and test the scale with EFA To perform these two techniques, the author uses SPSS 22 software, after full input and cleaning of the data, the author performs Cronbach's Alpha analysis, then performs EFA 3.3.2 Formal research 3.3.2.1 Objective of formal research After a preliminary assessment of the scale in the preliminary study, the author will have official scales of each research concept and conduct a formal test of the scale The goal of this formal quantitative study is to re-examine the scale, test hypotheses in the research model to address the five research objectives 3.3.2.2 Methods and contents of formal research The method used in the formal research was the survey method - The data collection tool in the formal research was a detailed questionnaire The author conducts direct and indirect surveys of individuals directly using the AIS and individuals involved in the use of AIS in the ERP Authors conduct surveys in a variety of approach, such as direct questionnaires or online survey via email - Sample size: A formal research using the CFA to test scale values and CB-SEM model to test hypotheses The CFA technique provides a test of composite reliability, covariance, unidirectional, convergent and discriminant values of the scale CB-SEM analysis allows us to test the relationship between concepts in the research model For the purposes of this study, the study of the structure of 13 the observed variables, the re-examination of the theory, the comparison of the theories with the selected research model, thus, CB-SEM was selected by the author According to Barrett (2007), the minimum sample size used in CB-SEM analysis is 200 According to Bollen (1989), the proportions required to design a sample size are at least five mandates for each parameter (5:1) to achieve reliability in the study In this study, the author used the minimum sample size determination in the SEM analysis The study was conducted mainly in enterprises in Ho Chi Minh City and other provinces from August to September 2018 3.3.2.3 Data processing tools In order to achieve the detailed research objectives set out, in the formal research, the author used CFA and CB-SEM Confirmatory Factor Analysis (CFA) After analyzing EFA and having a formal measurement model CFA analysis will help to validate the measurement model, the required scale is good Scales need to meet criteria that can be used in scientific research and research testing According to Nguyen Dinh Tho (2013), three important properties of a scale are: (1) direction of the scale (single or multidirectional scale), (2) reliability and (3) the value of the scale The value of the scale consists of the main categories: content value, convergence value, differential value, theoretical value Structural Equation Analysis (CB-SEM) CB-SEM analysis is used to test the theoretical value of the scale, test the relationships in the research model Indicators that measure the fit of the model to market data are quite similar to the CFA analysis In addition, after analyzing the SEM, the author continues to implement the Bootstrap method to evaluate the reliability of the estimates for the purpose of extending the overall study results Chapter 4: Findings and Discussion This chapter focuses on the results of preliminary research and formal research Specifically: - The results of the preliminary study, namely the description the research sample in the preliminary study, the results of Cronbach's Alpha coefficient analysis and the EFA Based on the results of the analysis, having official scale and adjustment of the research model - The results of the formal study, namely the results of the CFA and CB-SEM model to evaluate the measurement model and the structural model The results will explain the relationships in the research model, thereby explaining the research objectives - Analyzing the role of the intermediate variable is the perceived usefulness of AIS for the relationship between variables in the research model - Verify the relationship between the factors of the individual characteristics of the survey object and the using of AIS - Discuss the results of the research, compare and evaluate the research results of this research with the researches have been done 4.1 Findings of preliminary research Preliminary research was conducted from July to August 2018, the author sent 50 paper surveys to the subjects including accountant and managers participating in the use of AIS, collected was 48 sheets, after eliminating the non-response full surveys, the remaining 21 sheets (42%) In addition, the author emailed 85 14 respondents, collected 83 responses (98%) Thus, the total sample size used was 104, collected from 104 individuals surveyed in 70 enterprises 4.1.1 Description sample of preliminary research The sample consisted of 71 individuals (68.3%) and 33 managers use of AIS (31.7%), 37 males (35, 6%) and 67 female (64.4%) The number of respondents aged 30 to 40 was the highest at 62 (59.6%) Qualifications account for the highest proportion (69.2%), followed by postgraduate (20.2%) and college (10.6%) The working experience of the staff is highest, ranging from to 10 years (43.3%) The working experience under years accounts for 38.5% and the working experience over 10 years is 18.3% These people are working in a variety of businesses, including 30 limited liability companies (42.9%), 29 jointstock companies (41.4%), and 11 enterprises including state-owned enterprises, joint venture enterprises and private enterprises (15.7%) Regarding business activities of the enterprise, the author classifies cases, the first is the trade and services with 54.7%, the second is the production with 31.4 %, the third is the construction with 7%, the fourth is the financial investment accounted for 4.7%, the last is the field of education and training and other sectors with 2.4% The size of enterprises in the sample also varies, with the majority being large enterprises with 70%, medium enterprises accounting for 20%, small enterprises accounting for 10% 4.1.2 The result of test the scales with Cronbach’s Alpha The results show that these concepts are internally consistent The Cronbach’s Alpha coefficients for each of the concepts > 0.8 are very good Observing variables with a coefficient of correlation is greater than 0.3 However, only the concept of working environment (WE) has Cronbach's Alpha lower but still > 0.6, which is acceptable For the concept use of AIS, if eliminating ASU1 variable, the Alpha coefficient will increase to 0.911 (from 0.859 to 0.911), so ASU1 will be excluded from the scale of the concept use of AIS (ASU) 4.1.3 The result of EFA After evaluating the reliability of the scale with the Cronbach's Alpha coefficient, ASU1 variable is removed, and the scale satisfy the reliability requirement Next, observational variables will continue to be evaluated with EFA The results of the two EFA for the variables showed that the KMO = 0.851 was > 0.5 and < The Bartlett test showed p-value