Recent public health studies made headlines, 1-3 reporting that for some subpopulations in the USA, mortality rates have been higher and life expectancies lower for recent compared with earlier time periods. 4-7 These patterns have been described in both popular and academic discourse as a 'rise' in mortality or a 'decline' in life expectancy. We suggest that it is long past time to admit an alternative-and arguably more plausible-interpretation of these patterns. The fact that a measure was computed at two different time points does not, by itself, make the difference between them a trend. Imagine if researchers measured the average temperature for the whole of the USA a decade ago, and then for only Alaska this year, and found the former number to be lower than the latter. Would it be appropriate to say that average temperatures had 'declined' over the decade? We argue that it would not, and that it is likewise not appropriate to be describing many of the observed differences in subgroup life expectancy or mortality as 'trends'. Nevertheless, scholars and journalists alike have quickly adopted this 'trend' conclusion and given short shrift to an alternative interpretation that we find far more plausible. Here, we make the case that this alternative explanation should be the subject of serious empirical investigation and discussion in scholarly and public discourse, rather than getting the treatment it gets nowwhich is a cursory dismissal relegated to the 'limitations' sections of academic papers. We take seriously the reality of health disparities in the USA and the research and policy attention that they demand; understanding and redressing these disparities requires that trends be accurately characterized.

Abstract. How does specific information about contamination in a household's drinking water affect water handling behavior? We randomly split a sample of households in rural Andhra Pradesh, India. The treatment group observed a contamination test of the drinking water in their own household storage vessel; while they were waiting for their results, they were also provided with a list of actions that they could take to remedy contamination if they tested positive. The control group received no test or guidance. The drinking water of nearly 90% of tested households showed evidence of contamination by fecal bacteria. They reacted by purchasing more of their water from commercial sources but not by making more time-intensive adjustments. Providing salient evidence of risk increases demand for commercial clean water.

Provocative studies have reported that in the United States, marriages producing firstborn daughters are more likely to divorce than those producing firstborn sons. The findings have been interpreted as contemporary evidence of fathers' son preference. Our study explores the potential role of another set of dynamics that may drive these patterns: namely, selection into live birth. Epidemiological evidence indicates that the characteristic female survival advantage may begin before birth. If stress accompanying unstable marriages has biological effects on fecundity, a female survival advantage could generate an association between stability and the sex composition of offspring. Combining regression and simulation techniques to analyze real-world data, we ask, How much of the observed association between sex of the firstborn child and risk of divorce could plausibly be accounted for by the joint effects of female survival advantage and reduced fecundity associated with unstable marriage? Using data from the National Longitudinal Survey of Youth (NLSY79), we find that relationship conflict predicts the sex of children born after conflict was measured; conflict also predicts subsequent divorce. Conservative specification of parameters linking pregnancy characteristics, selection into live birth, and divorce are sufficient to generate a selection-driven association between offspring sex and divorce, which is consequential in magnitude. Our findings illustrate the value of demographic accounting of processes which occur before birth—a period when many outcomes of central interest in the population sciences begin to take shape.

Levels and changes in the value of exports and imports divided by aggregate GDP (the trade/GDP ratio) are occasionally used as measures of trade "openness." The oft-quoted work of Dollar and Kraay (2001) and the World Bank (2002) uses changes in the trade/GDP as a basis for classifying countries as "globalizers" or "non-globalizers. " We argue that neither the level nor the change in a country's trade/GDP ratio can be taken as an indication of the "openness" of a country's trade policy. In particular, we examine the ways in which terms of trade shifts have affected trade/GDP ratio over the past two decades. While commodity prices were high in the early 1980s, commodity producing countries financed large trade deficits with expected export revenue. When the prices collapsed, their capacity to import fell precipitously and they were forced to close their trade deficits in order to balance the current account. Since the numerator of the trade/GDP ratio includes the sum of exports and imports, and the denominator includes the trade balance, this adjustment resulted in a decline and then stagnation in the trade/GDP ratio. Therefore, using stagnant or declining trade/GDP ratios to identify countries that are less "open" systematically picks out those countries that are highly dependent on commodities for their export revenue. Because these same countries have experienced stagnant or negative economic growth over the past two decades, the empirical evidence offered by Dollar and Kraay overstates the importance of trade policy in economic growth. Adding a "commodity dependence" dummy variable to their growth regressions reduces the magnitude of the apparent "growth effect" of their "openness" variable at least by half. We briefly review the literature on the relationships between commodity dependence and slow growth, highlighting that the whole question of "openness" vs. "closedness" is orthogonal to the problems of poor, slow growing, commodity producing countries.