This article describes and field-tests the improvement rate difference (IRD), a new effect size for summarizing single-case research data. Termed “risk difference” in medical research, IRD expresses the difference in successful performance between baseline and intervention phases. IRD can be calculated from visual analysis of nonoverlapping data, and is easily explained to most educators. IRD entails few data assumptions and has confidence intervals. The article applies IRD to 166 published data series, correlates results with three other effect sizes: R2, Kruskal-Wallis W, and percent of nonoverlapping data (PND), and reports interrater reliability of the IRD hand scoring. The major finding is that IRD is a promising effect size for single-case research.

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Five experiments tested the idea that instructing a witness to close their eyes during retrieval might increase retrieval success. In Experiment 1 participants watched a video, before a cued-recall test for which they were either instructed to close their eyes, or received no-instructions. Eye-closure led to an increase in correct cued-recall, with no increase in incorrect responses. Experiments 2-5 sought to test the generality of this effect over variations in study material (video or live interaction), test format (cued- or free-recall) and information modality (visual or auditory details recalled). Overall, eye-closure increased recall of both visual detail and auditory details, with no accompanying increase in recall of false details. Collectively, these data convincingly demonstrate the benefits of eye-closure as an aid to retrieval, and offer insight into why hypnosis, which usually involves eye-closure, may facilitate eyewitness recall.

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The problem of identifying areas of accelerated erosion in a dynamic landscape is complicated. The limited history of sediment yield measurements makes this task difficult even if geomorphic evidence is available. Beryllium-10, a cosmogenic isotope produced by cosmic rays interacting with the earth's atmosphere and surface, has chemical and physical properties that make it useful as a tracer for erosion and sediment transport processes. The rarity of the stable isotope, 9Be, allows "Be to be detected with accelerator mass spectrometry in natural materials at extremely low levels. Backgrounds for rocks and sediments below lo5 atom per g are now attainable, a value to be compared with an average deposition rate of 1.3 x lo6 atom cm-2 yr-l. The affinity of Be for the components of soil and sediment is sufficiently high that it is effectively immobilized on contact, thereby allowing "Be to function as a tracer of sediment transport. TO a good approximation all the "Be transport out of a drainage basin is on the sediment leaving it. The number of "Be atoms passing the gauging station can be determined by measuring the concentration of the isotope in the sediment, if the annual sediment load is known. The ratio of the "Be carried from the basin by the sediment to that incident upon it, called the erosion index, has been determined for 48 drainage basins within the same physiographic province, which allows them to be reasonably compared, all of whieh have sediment yield data. Basins located in the Atlantic coastal plain have an average index of 0.3 with the maximum observed being 0.9. Basins located between the fall line and the mountains, a region called the Piedmont, have an average value of 2.2 with individual values ranging from 0.6 to 6.7; this marked difference is thought to result from two centuries of farming on land of moderate gradient. Basins in the highland regions reflect local conditions with low indices for those in grass and timber and high indices associated with destructive land use. The data allow an estimate of the erosion index for the pre-colonial Piedmont, which then allows the precolonial sediment yield to be calculated. A number of basins have also been examined world wide with similar conclusions derived. An important deviation from the rule is noted for rivers that erode large regions of loess, such as the Mississippi, Hwang Ho, and Yangtze. Large aeolian deposits were laid down during the ice age in these basins, deposits that brought inherited "Be with them and that are easily eroded.. . ,

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