Does the method of entrusted lending via farmer-based unions facilitate low-income households’ access to bank credit? evidence from northwestern vietnam

Nội dung text: Does the method of entrusted lending via farmer-based unions facilitate low-income households’ access to bank credit? evidence from northwestern vietnam

1. TNU Journal of Science and Technology 226(03): 11 - 19 DOES THE METHOD OF ENTRUSTED LENDING VIA FARMER-BASED UNIONS FACILITATE LOW-INCOME HOUSEHOLDS’ ACCESS TO BANK CREDIT? EVIDENCE FROM NORTHWESTERN VIETNAM * Do Xuan Luan TNU - University of Agriculture and Forestry ARTICLE INFO ABSTRACT Received: 07/4/2020 This paper aims to examine the hypothesis that the method of entrusted lending via farmer-based unions is significant to resolve information Revised: 22/5/2020 asymmetries and facilitate households’ access to bank credit. This paper Published: 10/6/2020 uses binary logistic regression models applied to data collected from a survey of 548 cinnamon households in Northwestern Vietnam. Results KEYWORDS show that membership to a farmer-based union facilitates households’ access to collateral-free credit. Unions help banks to better select Access to credit creditworthy households, conduct group lending to reduce risk of default Households and transaction costs. The successful factor of unions can be explained by the fact that unions exploit local knowledge to conduct group lending, Farmer-based unions thereby help to resolve information asymmetries in farm credit markets. To Northwestern bridge the credit gap, more regular trainings for the leaders of unions and Vietnam the groups of credit and savings are needed. In addition, a digital database is useful to share reliable information between banks and unions regarding relevant entrustment issues. The results contribute to the practical actions by suggesting a feasible policy intervention for addressing the problem of information asymmetries in farm credit markets. PH N H C CHO A H C QUA C C CH C N N D N C H C I P C N N D N N N H N C A C C H HU NH P H P H N N CH N N C I NAM L g i h g – h i gu H N IN I O M T Ngày h bài: 07/4/2020 c ch c a b i vi t n y nh m ki m nh gi thuy t cho r ng ph ng th c cho vay y th c th ng qua c c t ch c c a n ng d n c ngh a Ngày hoà thiện: 22/5/2020 trong kh c ph c b t c n x ng th ng tin v th c y ti p c n t n d ng Ngày đă g: 10/6/2020 ng n h ng c a c c h gia nh. i vi t s d ng m h nh h i quy logistic v i d li u c thu th p t kh o s t h tr ng qu T y T H A c Vi t am. t qu cho th y th nh vi n trong c c t ch c n ng d n tạo iều ki n cho c c h gia nh ti p c n v i t n d ng ng n h ng kh ng T n d ng c n t i s n th ch p. c t ch c h i gi p ng n h ng l a ch n t t h n H gia nh c c h gia nh c nhu c u vay v n t ch c cho vay theo nh m qua T ch c n ng d n gi m r i ro v chi ph giao d ch. Th nh c ng c a c c t ch c h i c th do h khai th c ki n th c a ph ng ti n h nh cho vay theo T y c nh m qua gi p kh c ph c b t c n x ng th ng tin trong th tr ng t n Vi t am d ng n ng nghi p. C n t ch c c c kh a o tạo th ng xuy n cho c n b c a c c h i v c c t ti t ki m vay v n thu hẹp kho ng c ch t n d ng; x y d ng s d li u s chia s th ng tin gi a c c ng n h ng v c c h i li n quan n c c v n ề y th c cho vay. t qu nghi n c u cũng ề xu t c c can thi p ch nh s ch kh thi gi i quy t v n ề b t c n x ng th ng tin trong th tr ng t n d ng n ng nghi p. DOI: *Email: doxuanluan@tuaf.edu.vn 11 Email: jst@tnu.edu.vn
2. TNU Journal of Science and Technology 226(03): 11 - 19 1. Introduction Sufficient access to credit is crucial to improve farmers’ income [1]. Unfortunately access constraints have adverse effects on their ability to invest [2]. Lack of collaterals and high transaction costs due to information asymmetries have prevented a number of farm households from accessing to credit [3]. On the supply side, banks find it hard to evaluate the possible risks and repayment capacity of applicants. Banks face higher costs of selecting, controlling and enforcing borrowers to repay. In the field of rural credit, few studies examined on how to resolve the problem of information asymmetries to narrow the gap between credit demand and supply. This study contributes to the literature by answering a main research question: Does the method of entrusted lending via farmer-based unions facilitate low-income households’ access to bank credit? Lending entrustment means that farmer-based unions such as farmers’ unions women’s unions receive entrusted fund from banks via entrustment agreement for lending to their clients. A case study was made from the cinnamon-farming households in Northwestern Vietnam. Cinnamon has been seen as the most aromatic medicinal plant with high concentration of essential oils, sweet flavour which are beneficial to health care [4]. Farmers need credit incentives to improve the quality of cinnamon materials which are later used in the pharmaceutical sector. 2. Methodology 2.1. Data collection Cinnamon is mainly planted in Yen Bai province, which is home to the most vulnerable, socially excluded ethnic communities in the country [5]. The growing demand from international markets for high quality cinnamon products being used for food, medicine and essential oils also creates challenges for farm households who are involved in the growing stage of cinnamon trees. Van Yen from the Northwest, Van Chan from the West and Tran Yen from the Northern part of the province were the three districts selected for collecting primary data. Table 1. Decomposition of household sample size Districts Communes Sample households Sampling rate (%) Dai Son 73 13.32 Vien Son 68 12.41 Mo Vang 30 5.47 Chau Que Ha 25 4.56 Van Yen Yen Phu 30 5.47 Phong Du Thuong 25 4.56 Xuan Tam 26 4.74 Tan Hop 42 7.66 Quy Mong 30 5.47 Kien Thanh 30 5.47 Tran Yen Y Can 30 5.47 Dao Thinh 30 5.47 Nam Lanh 28 5.11 Nam Muoi 28 5.11 Van Chan Nam Bung 25 4.56 Son Luong 28 5.11 Total 16 communes 548 100.00 A household survey was made between August 2017 to March 2018, using a structured questionnaire focusing on the role of unions in facilitating household access to bank credit. The number of households was approximated to the proportion of cinnamon area based on 12 Email: jst@tnu.edu.vn
3. TNU Journal of Science and Technology 226(03): 11 - 19 consultation with village leaders. The sample size contains 548 cinnamon producing households from 16 communes in three districts (Table 1). In addition, in-depth interviews with unions and banks are made to inquire information about credit access issues. 2.2. Conceptual framework Farmer- Based Unions •Capital mobilisation •To resolve •Legal documents •Business strategies information •Risk control assymetries; •Credit use plan •Legal regulations •Briding the •Collateral credit gap •Social network between demand •Farming pofitability and supply CREDIT CREDIT SUPPLY DEMAND Figure 1. A conceptual framework of the study (Source: own formulation) In this study, the conceptual framework as shown in Figure 1 focuses on the role of farmer- based unions in bringing farmers and banks together. On the demand side farmer’s access to credit might depend on various drivers such as ethnicity, education of the household head, family size, farm size, access to trainings, property rights through land use certificates and access to bank accounts [6]. On the credit supply side, the lending decisions of banks depend heavily on their lending policies. To better serve clients, banks need to improve their credit transaction models, renew financial products and simplify the procedure in order to reduce transaction costs. These are precondition factors to sustain the monetary business activities for banks. To bridge the credit gap between demand and supply, local unions assist banks with accessing information regarding farming performance and households with credit source availability. The partnerships between banks, unions and farmers allow each partner to encourage their strengths and have been seen as a promising instrument for farming investment. When credit demand and supply are connected, banks can serve more clients, increase loan disbursement volumes and earn profits. To the demand side, credit helps borrowers expand investment and improve the quality of farming products. The narrowing credit gap can serve an important role in rural economic development and poverty reduction. 2.3. A binary logistic regression model Theoretically, if the projected benefit to apply credit is positive, then a household might choose to apply credit and vice versa. The net benefit can be denoted by , which is a latent variable reflecting the net benefit of using credit. (1) Where: Ci, denotes the credit status of the household which equals one if the household accessed bank credit and otherwise zero. Credit access status is explained by household endowments. Mathematically, the probability of taking out a loan is written as follows: 13 Email: jst@tnu.edu.vn
4. TNU Journal of Science and Technology 226(03): 11 - 19 (4) ( ) ∫ ( ) √ For β is a k by 1 vector of parameters to be estimated. is the n by k matrix of the explanatory variables. In reality, is not observable and only variable for accessing to a loan is observable. To measure the probability of accessing credit, this study applies a logistic model. The dependent variable, a dichotomous variable (with and without access to credit), is assumed to be linearly related to explanatory variables. The model is described as: [ ] (5) Where: ln = natural logarithm, P = probability of accessing to credit, 1 P = probability of not accessing credit βn = coefficients of explanatory variables, Xn = predictor variables, and = error term. The explanatory variables of access to credit by cinnamon households are derived from a literature review and local consultants (Table 2). Table 2. Description of selected variables Expected Dimension Variables Definition and measurement Type a signs Age Age of the household head (years) C + Age square Age squared of the household head, (years squared) C +/- Cinnamon Education Number of years in school (years) C + farmers Ethnicity of the household head (=1 if the Ethnicity D +/- household head is the Kinh majority; 0 otherwise Membership status of local unions (=1 if the household has at least one person who is a member Union D + of a women’s union or a farmers’ union; 0 otherwise) Household size Total number of family members (persons) C + Distance to main The distance in kilometres from the house to the C - market nearest bank Market visits Frequency of market visits per week (visits) C + Cinnamon farm size Total cinnamon farm size (hectares) C +/- Cinnamon If the loan needs to be secured by a red book Collateral requirement D + households (1=Yes, 0 otherwise) Ownership of a bank account (=1 if the household Bank account D + has a bank account and 0 otherwise) Training A dummy that equals one if the farmer attended a D + training course (e.g. farming technical assistance) Van Yen Capture geographical indication of cinnamon D + production (=1 if households locate in Van Yen district, 0 otherwise) Van Chan Dummy =1 if households locate in Van Chan D - district, 0 otherwise Note: aD = discontinuous variables; C = Continuous variables 2.3.1. Variable of interest Union membership is a variable of the most interest. In Vietnam women’s unions and farmers’ unions represent a very specific feature of the country’s political and socio-economic landscape and serve a major role in financial inclusion in Vietnam. Union membership enhances 14 Email: jst@tnu.edu.vn
5. TNU Journal of Science and Technology 226(03): 11 - 19 family networks which perform key functions as gateways to the formal credit and direct marketing channels [7]. It is hypothesized that being a member of unions can give cinnamon households a higher chance to access to credit, particularly preferential credit. 2.3.2. Control variables Age and age square of household heads might link to knowledge, experience, economic decision-making and life cycle to earn income [8]. It is hypothesized that educated household heads are more active to respond to the market and run their cinnamon farming activities more effectively. Educated farmers are expected to be more likely to perceive credit use, implying positive correlations between educational level and access to credit [9]. Ethnic minorities, making up 15% of the population in Vietnam have lower living standards than ‘majority’ inh and Hoa households [10]. The government has granted preferential credit to ethnic minorities in substantial efforts to promote equal development among ethnic groups of the country. This study therefore assumes that ethnic minorities are more likely to receive preferential credit but less likely to receive commercial credit. Larger households might also imply a higher number of labourers and higher income. It is therefore assumed that households with a larger number of members are more likely to have access to credit. Poor access to roads and transport has a severe impact on marketing of farming products [11]. The study assumes that the further distance to the nearest market centre is negatively associated with access to formal credit for cinnamon households. A larger farm size is more efficient compared to smaller farms due to the economics of scale. However, smaller farms might be easier to manage compared to larger farms, implying a negative correlation between farm size and access to credit. This study assumes that that there could be a positive or negative correlation between farm size and access to credit. Collateral, often seen as prerequisite to receiving loans from financial institutions, reflects the security against a loan for future business performance. Commercial banks use collateral to mitigate the inherently risky repayment of borrowers. Therefore, it is hypothesized that collateral in terms of land use certificates will be positively correlated with cinnamon farmers’ access to Agribank credit. Having a bank account encourages rural households to accumulate savings and increase their financial literacy [12]. This study hypothesized that households with access to bank accounts relax their borrowing constraints from banks. Agricultural training can reduce access barriers to credit and eliminate misuse of agriculture credit. Thus, this study hypothesized that there is a positive relationship between access to training and access to credit for farmers. Geographical indications encourage quality and reputation attributable to farming products [13]. It is therefore hypothesized geographical identities of cinnamon farming in Van Yen have a positive impact on farmers’ access to credit. 3. Results and discussion 3.1. Main characteristics of households The characteristics of sampled households are presented in Table 3. Among cinnamon households with access to credit, 11.86%, and 39.78% have access to Vietnam Bank for Agriculture and Rural Development (Agribank) and Vietnam Bank for Social Policy (VBSP) credit respectively. Farmers need credit in order to pay for labour during harvesting seasons, purchase grass-cutting machines, sawing machines, bark dryer, storage facilities and improved drying yards. The credit duration depends on the policy of the bank, the type of credit and the 15 Email: jst@tnu.edu.vn
6. TNU Journal of Science and Technology 226(03): 11 - 19 amount of credit applied for. A farmer can apply for the Agribank credit by completing an application form and providing collateral in the form of land and houses with proof of land title (red books). Table 3. Main characteristics of sampled farmers and households Van Yen Van Chan Tran Yen Overall Dimension Variable (n=319) (n=109) (n=120) (n=548) 44.8 40.6 47.1 44.4 Age (years) (10.85) (9.88) (10.74) (10.83) Cinnamon 6.2 7.4 6.7 6.5 Education (years) farmers a (3.98) (4.33) (2.89) (3.87) 0.28 0.18 0.40 0.28 Ethnicity (0-1) (0.45) (0.38) (0.49) (0.45) 0.22 0.19 0.32 0.24 Union (0-1) (0.42) (0.39) (0.47) (0.42) Household size 4.6 4.9 4.3 4.6 (persons) (1.57) (1.74) (1.48) (1.60) Distance to main 5.7 21.6 4. 9 8.7 market (km) (5.69) (11.54) (3.01) (9.40) Market visits (visits 1.74 1.11 1.51 1.56 Cinnamon per week) (1.33) (1.02) (1.39) (1.31) households a Cinnamon farm size 2.7 0.9 1.4 2.1 (hectares) (3.36) (1.10) (1.22) (2.78) Collateral requirement 0.16 0.17 0.25 0.18 (0-1) (0.37) (0.38) (0.43) (0.39) 0.09 0.09 0.27 0.13 Bank account (0-1) (0.28) (0.28) (0.44) (0.33) 0.14 0.11 0.26 0.16 Training (0-1) (0.35) (0.32) (0.44) (0.37) Access to Agribank (%) 14.73 7.34 8.33 11.86 credit b VBSP (%) 32.28 45.87 54.16 39.78 Note: a Mean value with standard errors in parentheses; b Percentage of respondents who have previously obtained credit from the type of provider Farmers can also apply for a preferential credit program, offered by the VBSP subsidised by the Vietnamese government. To obtain credit from the VBSP, an applicant needs to be in the list of applicants approved by the commune people’s committees. All 39.7 % of households which received preferential credit need to be membership in credit and savings groups to receive credit through unions such as women’s unions or farmers’ unions. 3.2. Lending characteristics by banks Lending characteristics of two banks are presented in Table 4. The VBSP has disbursed loans according to the governmental lending program. Households received subsidies from preferential credit programs. The overdue debt of credit disbursed through local unions from the VBSP is much lower than that of the Agribank. The Agribank still relies on collateral in the form of land use certificates. One difficulty for households is due to the problem of family separation leading to a case that many households do not have a certificate of land use rights. Multi-generation families separate and one land use certificate is used for multiple smaller size families, meaning that only one can use the land use certificate to apply for credit. 16 Email: jst@tnu.edu.vn
7. TNU Journal of Science and Technology 226(03): 11 - 19 Table 4. Lending characteristics by banks Characteristics VBSP Agribank Poor and near-poor households; Wealthier households; enterprises; Targeted clients 11 lending programs cooperatives and farms Credit value not exceeds 70% of Maximum amount 50 million dong collateral value Overdue debt 0.39% of total amount disbursed 3% of total amount disbursed Duration 3-5 years Flexible, depends on contracts Monthly interest 0.65%-0.90% Around 1%, flexible, depends on credit rate (%) contracts Collateral Strictly collateral requirement (fixed No collateral requirement requirement assets or land use certificate) Group lending Lending model Individual lending via women’s and farmers’ unions Based on the governmental targeting Lending conditions Based on market mechanism and policies Monthly or quarterly repayment Month or quarterly repayment Loan repayment Interest rate collection and principal Interest rate collection and principle at at the communal branches the bank branches Capital availability Depend on government budget Depend on deposit mobilization and borrower The bank is less involved in The bank is closely involved in selecting selection selecting borrowers borrowers 3.3. The role of farmer-based unions in facilitating households’ access to bank credit The results from a logistic estimate of the probability that a household has access to credit are presented in Table 5. Results show that access to Agribank credit is not contingent upon union membership. It depends on the availability of collateral, stable income and a good business plan. However, membership to a union is significant at 1% and positively related the probability of households’ access to preferential credit. In other words cinnamon households that join a union have a higher probability of accessing preferential credit. The finding in this study conforms to previous studies with data collection in other countries. Social unions also serve as the guarantee to improve their members’ access to credit without asset collateral security in rural Philippines [14]. Frequent meetings in group lending can serve as insurance to strengthen the ability of smallholder farmers to access financial services [15]. The education of household heads is positively associated with access to Agribank credit (P 0.10). This finding collaborates with those of in-depth interviews with banks which showed that secure property rights could be used as one of the most reliable lending criteria for the Agribank. Ownership of a bank account is positively and strongly (P < 0.01) correlated only with the access to overall credit and preferential credit. This result is consistent with the expectations, given that savings account is a component of rural financial inclusion. However, only 21% of adults and only 6% of the poor in Vietnam have bank accounts, which is very low compared to other countries in the world [16]. Being located in the most well-known cinnamon district was found to be the most significant variables influencing access to Agribank credit. The significant regional dummy variable 17 Email: jst@tnu.edu.vn
8. TNU Journal of Science and Technology 226(03): 11 - 19 suggests a higher granted credit in Van Yen compared to other districts. The explanation could be geographical indications of cinnamon products certified by the government to improve the cinnamon product management system, increase economic value for cinnamon products and generate income for farmers. Table 5. The impact of membership in farmer-based unions and other relevant factors on credit accessibility by cinnamon households Estimated coefficients (Standard error) Variables Dimension Agribank VBSP Overall 0.0319 -0.0647 -0.0474 Age (years) (0.1321) (0.0790) (0.0874) -0.00007 0.00048 0.00020 Age square (years squared) Cinnamon (0.0014) (0.0008) (0.0009) farmers 0.1015 -0.0484 -0.0106 Education (years) (0.0518) (0.0338) (0.0389) -0.0151 -0.5960 -0.9433 Ethnicity (0-1) (0.3916) (0.2879) (0.3793) 0.0783 3.4985 6.1209 Union (0-1) (0.4115) (0.3252) (1.0309) -0.1255 0.0797 0.0472 Household size (persons) (0.1169) (0.0746) (0.0905) 0.0279 0.0018 0.0088 Distance to main market (km) (0.0244) (0.0129) (0.0143) 0.1324 -0.0980 -0.1213 Market visits (visits) (0.1220) (0.0970) (0.1374) 0.0243 -0.0624 -0.0746 Cinnamon farm size (hectares) Cinnamon (0.0686) (0.0501) (0.0596) households 3.7384 0.4602 5.8104 Collateral requirement (0-1) (0.3889) (0.2859) (1.0348) 0.0591 1.0413 1.0544 Bank account (0-1) (0.4695 ) (0.3355) (0.4114) -0.4861 .05014 0.5303 Training (0-1) (0.4927) (0.3085) (0.3668) 1.4007 -0.7460 -0.3833 Van Yen (0-1) (0.4690) (0.3036) (0.3712) -0.5095 0.0860 -0.4928 Van Chan (0-1) (0.7228) (0.3881) (0.4756) -6.2317* 1.1107 0.9092 Intercept (3.0661) (1.8139) (2.0220) Model Percent correctly predicted 91.79% 80.47% 85.77% specification (N=548) Likelihood ratio test chi2, (14 152.12 235.97 393.06 degrees of freedom) Note: The dependent variable is a 0-1 i di ato of a ess to edit whe e 1= a ess to edit’ Sta da d errors are in parentheses with the estimates; * Significance at a 10% level; Significant at a 5% level; Significance at a 1% level. 4. Conclusions and policy implications Access to credit for farm households is a key part of the rural development and poverty reduction process. However, lack of access to credit remains a big challenge for farm development in general and for the cinnamon farming in particular. This study examines whether membership in a farmer-based union can facilitate household’s access to credit. 18 Email: jst@tnu.edu.vn
9. TNU Journal of Science and Technology 226(03): 11 - 19 The findings show that households need credit improve investment and the quality products which are later used for health care needs. Membership in a farmer-based union facilitates farmers’ access to collateral-free credit. It is therefore necessary to encourage farmers to join the unions to have convenient access to credit. Another finding is that commercial banks are hesitant to expand credit and require tangible collateral in the form of red books to be present as the most important condition for giving loans. Findings in this study provide insights for designing credit schemes for farm households in similar situations in other lower-income economies. The key lesson drawn is to take advantage of local knowledge to conduct group lending. Lending through farmer-based unions can address the problem of information asymmetry in farm credit markets. To enhance the role of farmer-based unions, trainings are crucial to enhance their capacity in financial management. Union staffs need to be equipped with knowledge to support farmers in running more profitable businesses. Acknowledgments This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 502.01-2016.12. REFERENCES [1] R. E. Isoto, A. G. Sam, and D. S. Kraybill, "Uninsured Health Shocks and Agricultural Productivity among Rural Households: The Mitigating Role of Micro-credit," The Journal of Development Studies, vol. 53, pp. 2050-2066, 2017. [2] M. Arouri, N. V. Cuong, and A. B. Youssef, "Natural Disasters, Household Welfare, and Resilience: Evidence from Rural Vietnam," World Development, vol. 70, pp. 59-77, 2015. [3] D. X. Luan, and N. T. L. Anh, "Poverty targeting and income impact of subsidised credit on accessed households in the Northern Mountainous Region of Vietnam," Journal of Agriculture and Rural Development in the Tropics and Subtropics, vol. 116, pp. 173-186, 2015. [4] P. V. Rao, and S. H. Gan, "Cinnamon: a multifaceted medicinal plant", Evidence-Based Complementary and Alternative Medicine, vol. 2014, pp. 1-12, 2014. [5] Yen Bai Statistics Office, Yen Bai Statistical Year Book. Hanoi: Statistical Publishing House, 2018. [6] P. D. Khoi, C. Gan, G. V. Nartea, and D. A. Cohen, "Formal and informal rural credit in the Mekong River Delta of Vietnam: Interaction and accessibility," Journal of Asian Economics, vol. 26, pp.1-13, 2013. [7] N. H. Chi, and C. J. Nordman, "Household Entrepreneurship and Social Networks: Panel Data Evidence from Vietnam," The Journal of Development Studies, vol. 54, pp.594-618, 2018. [8] C. Bai, B. Shi, F. Liu, and J. Sarkis, "Banking credit worthiness: Evaluating the complex relationships," Omega, vol.83, pp.26-38, 2018. [9] B. Baulch, T. T. K. Chuyen, D. Haughton, and J. Haughton, "Ethnic minority development in Vietnam," The Journal of Development Studies, vol. 43, pp.1151-1176, 2007. [10] N. L. Thanh, N. H. P. Anh, S. Van Passel, H. Azadi, and P. Lebailly, "Access to Preferential Loans for Poverty Reduction and Rural Development: Evidence from Vietnam," Journal of Economic Issues, vol.52, pp. 246-269, 2018. [11] R. Mu, and D. Van De Walle, "Rural Roads and Local Market Development in Vietnam," The Journal of Development Studies, vol. 47, pp.709-734, 2011. [12] G. Sen, and S. De, "How Much Does Having a Bank Account Help the Poor?" The Journal of Development Studies, vol.54, pp.1551-1571, 2018. [13] D. Marie-Vivien, and I. Vagneron, "One size fits all or tailor-made? Building appropriate certification systems for geographical indications in Southeast Asia," World Food Policy, vol.4, pp.105-126, 2017. [14] X. Giné and D. arlan, S. Dean, "Group versus individual liability: Short and long term evidence from Philippine microcredit lending groups," Journal of Development Economics, vol.107, pp.65-83, 2014. [15] J. De Quidt, T. Fetzer, and M. Ghatak, "Group lending without joint liability," Journal of Development Economics, vol.121, pp.217-236, 2016. [16] General Statistical Office, Statistical Handbook of Vietnam, Hanoi: Statistical Publishing House, 2018. 19 Email: jst@tnu.edu.vn