Bounding bias due to selection

When epidemiologic studies are conducted in a subset of the population, selection bias can threaten the validity of causal inference. This bias can occur whether or not that selected population is the target population, and can occur even in the absence of exposure-outcome confounding. However, it is often difficult to quantify the extent of selection bias, and sensitivity analysis can be challenging to undertake and to understand. In this article we demonstrate that the magnitude of the bias due to selection can be bounded by simple expressions defined by parameters characterizing the relationships between unmeasured factor(s) responsible for the bias and the measured variables. No functional form assumptions are necessary about those unmeasured factors. Using knowledge about the selection mechanism, researchers can account for the possible extent of selection bias by specifying the size of the parameters in the bounds. We also show that the bounds, which differ depending on the target population, result in summary measures that can be used to calculate the minimum magnitude of the parameters required to shift a risk ratio to the null. The summary measure can be used to determine the overall strength of selection that would be necessary to explain away a result. We then show that the bounds and summary measures can be simplified in certain contexts or with certain assumptions. Using examples with varying selection mechanisms, we also demonstrate how researchers can implement these simple sensitivity analyses

Cinderella's Lessons on Footbinding: How Tiny Feet Found their Way into the Chinese Cinderella Story

The story of Cinderella has had many variants, some dating back to ancient Tibetan trade routes and dynastic China. When the tale is analysed in comparison to other variants it is found that in the Chinese version Yeh-Shen (Cinderella) is prized for the small size of her feet. The result of Yeh-Shen having small feet in the story is that she is led her into wealth, power and marriage, the same pursuable goals that led to the custom of footbinding. In southern China the custom of footbinding became a historically defining feature of the society. A women's beauty and her delicacy were judged by the size of her feet, and small feet were the aim of the binding. Small feet played such an important role in the society that it can be found as early as the ninth century C.E., in the traditional oral story, Yeh-Shen

Interactive Effects of Intellectual Property Rights and Trade Openness on Economic Growth

This paper analyzes the interactive effect of trade openness and intellectual property rights (IPR) on economic growth. Recent literature suggests that IPR may work through the mechanisms of trade and FDI to affect growth. An IPR interaction with openness may aid in detecting this effect. This paper also analyzes whether this effect varies depending on income level of the country. Building from Gould and Gruben (1996), this empirical analysis uses a panel regression with 62 countries in ten year periods from 1980 to 2010. The results suggest that: (1) the interaction between trade openness and IPR is important in understanding the effect of IPR on growth; (2) this interaction plays a significant role in understanding the “U-shaped” effect of IPR on economic growth for countries with different levels of income. These findings suggest that effects of trade and FDI are important considerations for understanding IPR and growth. It also suggests but that the level of development a country is in also matters significantly

Lesbian brides: post-queer popular culture

The last decade has witnessed a proliferation of lesbian representations in European and North American popular culture, particularly within television drama and broader celebrity culture. The abundance of “positive” and “ordinary” representations of lesbians is widely celebrated as signifying progress in queer struggles for social equality. Yet, as this article details, the terms of the visibility extended to lesbians within popular culture often a rm ideals of hetero-patriarchal, white femininity. Focusing on the visual and narrative registers within which lesbian romances are mediated within television drama, this article examines the emergence of what we describe as “the lesbian normal.” Tracking the ways in which the lesbian normal is anchored in a longer history of “the normal gay,” it argues that the lesbian normal is indicative of the emergence of a broader post-feminist and post-queer popular culture, in which feminist and queer struggles are imagined as completed and belonging to the past. Post-queer popular culture is depoliticising in its e ects, diminishing the critical potential of feminist and queer politics, and silencing the actually existing conditions of inequality, prejudice, and stigma that continue to shape lesbian lives

Determining Transmission Loss from Measured External and Internal Acoustic Environments

An estimate of the internal acoustic environment in each internal cavity of a launch vehicle is needed to ensure survivability of Space Launch System (SLS) avionics. Currently, this is achieved by using the noise reduction database of heritage flight vehicles such as the Space Shuttle and Saturn V for liftoff and ascent flight conditions. Marshall Space Flight Center (MSFC) is conducting a series of transmission loss tests to verify and augment this method. For this test setup, an aluminum orthogrid curved panel representing 1/8th of the circumference of a section of the SLS main structure was mounted in between a reverberation chamber and an anechoic chamber. Transmission loss was measured across the panel using microphones. Data measured during this test will be used to estimate the internal acoustic environments for several of the SLS launch vehicle internal spaces