preliminary) We examine the role of changes in health on participation decisions of elderly in Mexico using the Mexican Health and Aging Study (2001-2003). A simultaneous equations model accounts for potential endogeneity of health. Preliminary results with a two-stage estimation method suggest that a better health causes a stronger attachment to the labor market, and finds no evidence that emp...

We report on a long-term monitoring campaign of 1E 1841−045, the 12-s anomalous X-ray pulsar and magnetar candidate at the center of the supernova remnant Kes73. We have obtained approximately monthly observations of the pulsar with the Rossi X-ray Timing Explorer (RXTE) spanning over two years, during which time 1E 1841−045 is found to be rotating with sufficient stability to derive a phase-co...

Rumelt’s (1991) widely cited paper presents estimates of the relative influence of industry, corporate, business unit, and other influences on business unit profitability. He finds corporations explain almost none of the variability in business unit profitability. Using a simultaneous equation model, we provide alternative estimates of the influence of industry and corporation on business unit ...

Fetal arrhythmias are not uncommon. The diagnosis of a fetal arrhythmia is challenging and normally requires referral for a detailed fetal echocardiogram. The first step in the ultrasound evaluation should be distinguishing whether the arrhythmia is an irregular rhythm, a bradycardia, or a tachycardia. This can be done by evaluating the arrhythmia using simultaneous atrial and ventricular M-mod...

The timing and order in which a set of events occur strongly influences whether people judge them to be causally related. But what do people think particular temporal patterns of events tell them about causal structure? And how do they integrate multiple pieces of temporal evidence? We present a behavioral experiment that explores human causal structure induction from multiple temporal patterns...

In a seminal paper Nagar (1959) obtained moment approximations for the k-class of estimators in a general static simultaneous equation model under the assumption that the structural disturbances were i.i.d and normally distributed. While it has been known for some time that the normality assumption can be relaxed when obtaining the bias approximation, it has not been demonstrated that the secon...

Necessary and sufficient conditions for Identlflability with linear coefficient and covarlance restrictions are developed. In practical terms, covarlance restrictions aid identification if and only if they imply either that (1) a set of endogenous variables is predetermined in a particular equation (generalizing the notion of recursiveness) or (11) an identifiable residual is predetermined in a...

This paper focuses on the connection between product complexity and vertical integration using original empirical evidence from the auto industry. A rich literature has addressed the choice between internal production and external sourcing of components in the auto industry. More recent literature has developed the concept of product architecture as another choice variable that may be one of th...

Poskitt and Skeels (2003) provide a new approximation to the sampling distribution of the IV estimator in a simultaneous equations model, the approximation is appropriate when the concentration parameter associated with the reduced form model is small. A basic purpose of this paper is to provide the practitioner with easily implemented inferential tools based upon extensions to these small conc...

A large body of empirical research has concluded that, at least during the 1950s and 1960s, the effect of welfare benefits on migration differed significantly by racial group, with blacks being attracted by and whites repulsed by areas that provided high welfare benefits. This study revisits the issue of racial differences in attractiveness to interregional differences in welfare benefits, usin...