Seatbelt and child restraint use among vehicle occupants in Ho Chi Minh City: an observational study in Vietnam

Abstract

This paper presents the trend of seatbelt use, disaggregated by vehicle occupants, in Ho Chi Minh City between 2016 and 2018. We conducted statistical analyses to identify the determinants of seatbelt use, including the effect of a new fine imposed against seatbelt law violation in the rear seats that became effective in January 2018. Seatbelt use was observed in at least half of all vehicle occupants, and drivers were more likely to use seatbelts than passengers. Only 4.4% of children younger than 5-years and 2.5% of 5 to12-year-olds used a child restraint system. Seatbelt use increased among all occupants after the imposed fine, especially among rear-seat passengers. Imposing new or increasing fixed penalties, with enforcement and public education, may increase seatbelt use to prevent road traffic injuries.     

Variance-ratio Statistics and High-frequency Data: Testing for Changes in Intraday Volatility Patterns

Variance-ratio tests are routinely employed to assess the variation in return volatility over time and across markets. However, such tests are not statistically robust and can be seriously misleading within a high-frequency context. We develop improved inference procedures using a Fourier Flexible Form regression framework. The practical significance is illustrated through tests for changes in the FX intraday volatility pattern following the removal of trading restrictions in Tokyo. Contrary to earlier evidence, we find nodiscernible changes outside of the Tokyo lunch period. We ascribe the difference to the fragile finite-sample inference of conventional variance-ratio procedures and a single outlier.     

Hoglex Demand Systems and Welfare Policy in Major Asean Developing Countries: A Bayesian Analysis Using Expenditure Unit Records

The HOGLEX demand system (Tran Van Hoa (1983, 1985)) is integrable and flexible in the sense that it is based on utility maximization and encompasses most other well-known demand systems (e.g., LINEX, AIDS) in the literature on consumer behaviour (Laitinen et al. (1983)). HOGLEX studies to date have been based on conventional OLS or MLE methods and panel aggregate income and price data, and restricted to investigating consumption patterns. The paper elaborates on three important subsets of the HOGLEX demand system and, using household expenditure unit records from two major ASEAN developing countries (i.e., Thailand and the Philippines), estimates by the Bayesian method these subsets for 20 socio-demographic cohorts, and discusses their substantial implications in social security and welfare policy analysis. We also estimate the models in the more practical case of measurement errors in total expenditure and compare the results with those without measurement errors.

     

A divisia system approach to modelling monetary aggregates

A complete system of Divisia partial adjustment asset equations based on the augmented-price expectations Baumol-Tobin inventory and transactions postulates is used to study the dynamic behaviour of monetary aggregates and their components in Australia during 1969.III to 1983.IV. The system provides a new and useful approach to modelling demand-for-money functions for effective monetary policy controls and targetting.     

Information technology: The need for social experiments

Highly industrialized societies are at present in a critical period, i.e., confronted with futures problems. Information technology is both the historically specific agent, which brought about the present critical period, and the basis for new developments in accordance with emerging new perceptions of the ideals of freedom and equality. Utilization of information technology in agreement with the new perceptions of these ideals requires renewal of the assumptions about the employee-place of work relationship and about the quality of knowledge, the infrastructure, and the decision-making processes of the highly industrialized societies. In order to explore the best uses of information technology under new assumptions, social experiments, as well as a clear understanding of the future as a historical concept among decision makers and participants, are imperative.     

Firm agglomeration and local poverty reduction: evidence from an economy in transition

We examine the linkages between firm agglomeration and the welfare of households in Vietnam. We measured firm agglomeration by per capita firm output at the district level and household welfare by per capita income, expenditure, and poverty. We find that firm agglomeration helps households move from the informal sector to the formal sector. As a result, there is a positive effect of firm agglomeration on per capita income, per capita expenditure, and poverty reduction, albeit of a small and time‐decreasing magnitude. The effect of firm agglomeration on per capita expenditure tends to be higher for households with men, younger, and more educated heads than households with women, older, and less educated heads. Households in rural areas and those that do not have crop land are more likely to benefit from firm agglomeration than those living in urban areas and having crop land.     

Media market concentration and pluralism

We study the relationship between market concentration and market variety, and thereby focus on two dimensions of variety, namely on internal variety and on external variety. In our setup, firms can expand their internal variety continuously around their focus point on a Salop‐circle. External variety then refers to the market supply of variety offered by all firms on the circle. We believe that this setting is particularly applicable to media. It turns out that in more concentrated markets, there is an incentive to provide more internal variety in order to compete for consumers. Then, the relationship between market concentration and external variety turns out to be ambiguous. There also exists no clear free market bias with respect to socially optimal internal and external variety.