Fetal Iodine Deficiency and Schooling: A Replication of Field,Robles, and Torero (2009)*

Scholars have theorized that congenital health endowment is an important determinant of economic outcomes later in a person's life. Field, Robles, and Torero (2009, American Economic Journal: Applied Economics 1, 140–169) find large increases in educational attainment caused by a reduction of fetal iodine deficiency following a set of iodine supplementation programs in Tanzania. We revisit the Tanzanian iodine programs with a narrow and wide replication of the study by Field et al. We are able to exactly replicate the original results. We find, however, that the findings are sensitive to alternative specification choices and sample restrictions. We try to address some of these concerns in the wide replication; we increase the sample size fourfold, and we improve the precision of the treatment variable by incorporating new institutional and medical insights. Despite the improvements, no effect is found. We conclude that the available data do not provide sufficient power to detect a possible effect, as treatment assignment cannot be measured with sufficient precision.     

A Sealed-Bid Two-Attribute Yardstick Auction Without Prior Scoring

We analyze a two-attribute single item procurement auction that uses yardstick competition to settle prices. The auction simplifies the procurement process by reducing the principal’s articulation of preferences to simply choosing the most preferred offer as if it was a market with posted prices. This is done simply by replacing the submitted sealed bids by yardstick bids, computed by a linear weighting of the other participants’ bids. We show that there is only one type of Nash equilibria where some agents may win the auction by submitting a zero price-bid. Using a simulation study we demonstrate that following this type of equilibrium behavior often leads to winner’s curse. The simulations show that in auctions with more than 12 participants the chance of facing winner’s curse is around 95 %. Truthful reporting, on the other hand, does not constitute a Nash equilibrium but it is ex post individually rational. Using a simulation study we demonstrate that truthful bidding may indeed represent some kind of focal point.     

Reserves and cash flows under stochastic retirement

Uncertain time of retirement and uncertain structure of retirement benefits are risk factors for life insurance companies. Nevertheless, classical life insurance models assume these are deterministic. In this paper, we include the risk from stochastic time of retirement and stochastic benefit structure in a classical finite-state Markov model for a life insurance contract. We include discontinuities in the distribution of the retirement time. First, we derive formulas for appropriate scaling of the benefits according to the time of retirement and discuss the link between the scaling and the guarantees provided. Stochastic retirement creates a need to rethink the construction of disability products for high ages and ways to handle this are discussed. We show how to calculate market reserves and how to use modified transition probabilities to calculate expected cash flows without significantly more complexity than in the traditional model. At last, we demonstrate the impact of stochastic retirement on market reserves and expected cash flow in numerical examples.     

Correlation in corporate defaults: Contagion or conditional independence?

We revisit a method used by Das et al. (2007) (DDKS) who jointly test and reject a specification of firm default intensities and the doubly stochastic assumption in intensity models of default. The method relies on a time change result for counting processes. With an almost identical set of default histories recorded by Moody’s in the period from 1982 to 2006, but using a different specification of the default intensity, we cannot reject the tests based on time change used in DDKS. We then note that the method proposed by DDKS is mainly a misspecification test in that it has very limited power in detecting violations of the doubly stochastic assumption. For example, it will not detect contagion which spreads through the explanatory variables “covariates” that determine the default intensities of individual firms. Therefore, we perform a different test using a Hawkes process alternative to see if firm-specific variables are affected by occurrences of defaults, but find no evidence of default contagion.     

How Productive Is Workplace Health and Safety?

In this paper, we investigate the causal impact of workplace health and safety practices on firm performance, using Danish longitudinal matched employer–employee data merged with unique cross‐sectional representative firm survey data on work environment conditions. We estimate standard production functions, augmented with workplace environment indicators, addressing both time‐invariant and time‐varying potentially relevant unobservables in the production process. We find positive and large productivity effects of improved physical dimensions of the health and safety environment, specifically, “internal climate” and “monotonous repetitive work”.     

Determining the cointegrating rank in nonstationary fractional systems by the exact local Whittle approach

We propose to extend the cointegration rank determination procedure of Robinson and Yajima [2002. Determination of cointegrating rank in fractional systems. Journal of Econometrics 106, 217–242] to accommodate both (asymptotically) stationary and nonstationary fractionally integrated processes as the common stochastic trends and cointegrating errors by applying the exact local Whittle analysis of Shimotsu and Phillips [2005. Exact local Whittle estimation of fractional integration. Annals of Statistics 33, 1890–1933]. The proposed method estimates the cointegrating rank by examining the rank of the spectral density matrix of the d$d$th differenced process around the origin, where the fractional integration order, d$d$, is estimated by the exact local Whittle estimator. Similar to other semiparametric methods, the approach advocated here only requires information about the behavior of the spectral density matrix around the origin, but it relies on a choice of (multiple) bandwidth(s) and threshold parameters. It does not require estimating the cointegrating vector(s) and is easier to implement than regression-based approaches, but it only provides a consistent estimate of the cointegration rank, and formal tests of the cointegration rank or levels of confidence are not available except for the special case of no cointegration. We apply the proposed methodology to the analysis of exchange rate dynamics among a system of seven exchange rates. Contrary to both fractional and integer-based parametric approaches, which indicate at most one cointegrating relation, our results suggest three or possibly four cointegrating relations in the data.     

The cointegrated vector autoregressive model with general deterministic terms

In the cointegrated vector autoregression (CVAR) literature, deterministic terms have until now been analyzed on a case-by-case, or as-needed basis. We give a comprehensive unified treatment of deterministic terms in the additive model $X_t=\gamma Z_t+Y_t$, where $Z_t$ belongs to a large class of deterministic regressors and $Y_t$ is a zero-mean CVAR. We suggest an extended model that can be estimated by reduced rank regression, and give a condition for when the additive and extended models are asymptotically equivalent, as well as an algorithm for deriving the additive model parameters from the extended model parameters. We derive asymptotic properties of the maximum likelihood estimators and discuss tests for rank and tests on the deterministic terms. In particular, we give conditions under which the estimators are asymptotically (mixed) Gaussian, such that associated tests are ${\chi }^2$-distributed.     

Market Integration of Fish in Europe

This paper examines market integration between fish species in Europe, taking international market integration into account. Based on Juselius (2006) , market integration is found both on the fresh and frozen markets. The Law of One Price is in force on the fresh market within the segments of flatfish and pelagic fish. Assuming transitivity, a loose form of market integration is identified between 13 fresh and seven frozen fish species, and the relative prices are found fairly stable. The policy implication is that catch limitation measures implemented through the Common Fisheries Policy have limited and conditional effects on prices, because of the large size of the market and varying market integration. Therefore, many fishermen are not ‘compensated’ by price increases as a result of catch limitation measures.