Measuring Confidentiality Risks in Census Data

Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies

Measuring Confidentiality Risks in Census Data

Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies

Effects of glyphosate-resistant crop cultivation on soil and water quality

Transgenic glyphosate-resistant crops (GRCs) have been com- mercialized and grown extensively in the western Hemisphere and, to a lesser extent, elsewhere. GRCs have generally become dominant in those countries where they have been approved for growing. Potential effects of glyphosate on soil and water are minimal, compared to the effects of the herbicides that are re- placed when GRCs are adopted. Perhaps the most important indirect effect is that GRCs crops promote the adoption of re- duced- or no-tillage agriculture, resulting in a signifcant reduc- tion in soil erosion and water contamination. Glyphosate and its degradation product, aminomethylphosphonate (AMPA), residues are not usually detected in high levels in ground or surface water in areas where glyphosate is used extensively. Furthermore, both glyphosate and AMPA are considered to be much more toxico- logically and environmentally benign than most of the herbicides replaced by glyphosate

Potential environmental impacts of herbicide-resistant crops.

Transgenic bromoxynil-, glufosinate-, and glyphosate-resistant crops have been commercialized and grown extensively in the Western Hemisphere and, to a lesser extent, elsewhere. Bromoxynil-resistant crops have been removed from the market. Few new herbicide-resistant crops (HRCs) are likely to be introduced in the near future. Glyphosate-resistant cotton and soybean have become dominant in those countries where they can be grown. Previous and potential effects of glufosinate and glyphosate on contamination of soil, water, and air are minimal, compared to that caused by the herbicides that they replace when HRCs are adopted. No risks have been found with food or feed safety or nutritional value in products from currently available HRCs. Both glufosinate- and glyphosate-resistant crops promote the adoption of reduced- or no-tillage agriculture. In the U.S.A. and Argentina, the advent of glyphosate-resistant soybeans resulted in a significant shift to reduced- and no-tillage practices, strongly reducing environmental degradation by agriculture. Weed species in HRC fields have shifted to those that can more successfully withstand glyphosate or to those that avoid the time of its application. One weed species has evolved resistance in glyphosate-resistant crops. HRCs have greater potential to become problems as volunteer crops than do conventional crops. In canola, herbicide resistance transgenes have been found in fields of canola that are supposed to be non transgenic. Under some circumstances, tansgene flow (introgression) to plants that might become problems in natural ecosystems may be the largest risk of HRCs. The HRC transgene itself is highly unlikely to be a risk in wild populations, but when linked to transgenes that may impart fitness benefits outside of agriculture, natural ecosystems could be affected. The development and use of failsafe introgression barriers in crops with such linked genes is highly encouraged