Statistical Decision Problems and Bayesian Nonparametric Methods

This paper considers parametric statistical decision problems conducted within a Bayesian nonparametric context. Our work was motivated by the realisation that typical parametric model selection procedures are essentially incoherent. We argue that one solution to this problem is to use a flexible enough model in the first place, a model that will not be checked no matter what data arrive. Ideally, one would use a nonparametric model to describe all the uncertainty about the density function generating the data. However, parametric models are the preferred choice for many statisticians, despite the incoherence involved in model checking, incoherence that is quite often ignored for pragmatic reasons. In this paper we show how coherent parametric inference can be carried out via decision theory and Bayesian nonparametrics. None of the ingredients discussed here are new, but our main point only becomes evident when one sees all priors—even parametric ones—as measures on sets of densities as opposed to measures on finite-dimensional parameter spaces.     

Stock market interdependence between Australia and its trading partners: does trade intensity matter?

We investigate the extent and manner of stock market interdependence between Australia and its trading partners and examine whether this is affected by trade intensity. Based on trade intensity, we classify Australia’s trading partners into major, medium and minor partners. We hypothesize that markets with greater (lower) trade intensity will be more (less) interdependent with Australia. We perform correlation (unconditional and conditional) analyses between Australia and its trading partners. Our results indicate that most of the markets that are highly correlated with Australia are its major trading partners. We conduct panel regression analysis to investigate whether trade intensity has any impact on the stock market correlations between Australia and its trading partners. The results show that trade intensity significantly and positively affect the correlations of Australia with its major trading partners. Thus, the results confirm our hypothesis that trade intensity drives stock market interdependence between Australia and its trading partners.     

How pervasive is the effect of culture on stock market linkages? Evidence across regions and economic cycles

We conduct a comprehensive study on the effect of culture on stock market linkages. With data on 25 national stock markets, a quantile regression model is used to estimate the determinants of market linkages using culture variable/s such as language, religion and Hofstede’s cultural dimensions while controlling for distance, economic and legal variables. Further, we test whether these effects hold across regions and if changes are detected during periods of market crisis. We also test if market liquidity, an indicator of market efficiency, diminishes the impact of culture on market linkages. The main conclusion is that culture preferences shape investor choices, which affects integration between stock markets. The equity markets with similar cultural traits tend to increase market linkages; however, we observe differences across regions. Furthermore, liquidity and economic uncertainty fail to have an impact on the significance of culture variable/s as determinants of market linkages.     

Can countries rely on foreign saving for investment and economic development?

Contrary to widespread presumption, a surprisingly large number of countries have been able to finance a significant fraction of their investment for extended periods using foreign finance. While many of these episodes are in countries where official finance is important, we also identify episodes where a substantial fraction of domestic investment is financed by private capital inflows. Although there is evidence of a positive growth effect of such inflows in the short run, that positive impact dissipates after 5 years and turns negative over longer horizons. Many such episodes end abruptly, with compression of the current account and sharp slowdowns in investment and growth. Summing over the inflow (current account deficit) episode and its aftermath, we find that growth is slower than when countries rely on domestic savings. The implication is that financing growth and investment out of foreign savings, while not impossible, is risky and too often counterproductive.     

Collaboration at work: An integrative multilevel conceptualization

The term collaboration has been used throughout a variety of research disciplines to describe multiple types of interaction; yet, a unified, comprehensive definition of the construct remains elusive. This lack of clarity regarding the distinctions and commonalities between collaboration and other interaction concepts has resulted in conceptual confusion that affects practice and research in human resource management. Practitioners see collaboration as more of a buzzword than as an effective human resource strategy. Previous theory development efforts have not yet taken a comprehensive multidisciplinary approach. This has resulted in failure to integrate key themes across disciplines into an overall view of collaboration, which is a commonplace practice in business and military sectors alike. This paper describes a multidisciplinary conceptualization of collaboration and discusses the implications of this integrative theory to human resource management and strategy development as well as future research efforts.     

A Proposed Model for Consumer-Based Brand Equity Analysis on Social Media Using Data Mining and Social Network Analysis

Online social networks have expanded their “virtual borders,” making the Internet more like an environment of social interaction than a business tool. However, even before the emergence and expansion of social media, marketing professionals were interested in identifying consumers' perceptions about brands. Thus, operational models have been proposed to facilitate such a task. Those models, however, can be expensive and inconvenient, since the models use questionnaires for data collection. To help overcome this problem, this article proposes a model for brand equity analysis from the consumer perspective expressed in social networks using opinion mining techniques and social network analysis. The application of the proposed model on data collected from Twitter made it possible to analyze five brand equity dimensions: brand awareness, brand loyalty, perceived sentiment, perceived quality, and brand associations. The results reached by the application of the model show that brand equity can be analyzed from data retrieved from virtual social networks, disclosing how consumers perceive brands in such an environment, without using questionnaires, enabling different brands in different contexts. Those data can be analyzed under both objective and replicable criteria for each of the brand equity elements that make up the model.     

Exploring sources and outcomes of trust and commitment to nonprofit organizations: The case of Amnesty International Portugal

The interactions between customers and organizations have been regarded as a core aspect in cocreating and developing new products and practices. The current study explores these interactions in the context of citizens and nonprofit organizations. The study comprises two parts: (a) a qualitative approach using interviews and the analysis of social networks to better understand the organization's social media marketing practices and corresponding outcomes and (b) a quantitative approach to analyze antecedents and outcomes of trust and being committed to participate in a nonprofit organization such as Amnesty International. From the qualitative approach, the findings highlight that Amnesty International uses social media (Facebook) to share information, and citizens tend to consider sharing posts, but they do not express new ideas or interact with the organization. These findings contribute to structure the model analyzed in the second stage of the research. Regarding the qualitative approach, the results show that organizational credibility is the most significant driver of trust followed by communicative ability. Affectively commitment to participation and relationship perception act as outcomes of overall commitment.     

Valuing the implicit guarantee of the Federal National Mortgage Association

The paper analyzes the guarantee of the Federal National Mortgage Association (FNMA). Rather than try to price the guarantee, we used time-series estimates of its value from Kane and Foster to infer the behavior of FNMA in exploiting the guarantee. The results are consistent with a model that predicts that FNMA does not take as much risk as it might. Rather, it trades off risk and return, but it does increase risk and exploit the guarantee when it gets in trouble (as it did in 1981).We have received helpful research assistance from Peter Carr and Bruno Gerard.     

Homeownership as a Constraint on Asset Allocation

Personal preferences and financial incentives make homeownership desirable for most families. Once a family purchases a home they find it impractical (costly) to frequently change their ownership of residential real estate. Thus, by deciding how much home to buy, a family constrains their ability to adjust their asset allocation between residential real estate and other assets. To analyze the impact of this constraint on consumption, welfare, and post-retirement wealth, we first investigate an individual’s optimal asset allocation decisions when they are subject to a “homeownership constraint.” Next, we perform a “thought experiment” where we assume the existence of a market where a homeowner can sell, without cost, a fractional interest in their home. Now the housing choice decision does not constrain the individual’s asset allocations. By comparing these two cases, we estimate the differences in post-retirement wealth and the welfare gains potentially realizable if asset allocations were not subject to a homeownership constraint. For realistic parameter values, we find that the homeowner would require a substantial increase in total net worth to achieve the same level of utility as would be achievable if the choice of a home could be separated from the asset allocation decision. The robustness of the analysis is evaluated with respect to the model’s parameters and initial state variables. We find that changes in the values of the constraint (i.e., the value of the home) and the expected real rate of home value appreciation are the only state variables or parameter that is associated with a large change in asset allocation and/or the burden imposed by the housing constraint. This finding suggests the importance of a detailed examination of the impact of inter-regional differences in home prices and expected rates of appreciation on asset allocation and post-retirement wealth.