RAND Corporation

About: RAND Corporation is a nonprofit organization based out in Santa Monica, California, United States. It is known for research contribution in the topics: Population & Health care. The organization has 9602 authors who have published 18570 publications receiving 744658 citations.

Inequalities for Stochastic Linear Programming Problems

Abstract: Consider a linear-programming problem in which the “right-hand side” is a random vector whose expected value is known and where the expected value of the objective function is to be minimized. An approximate solution is often found by replacing the “right-hand side” by its expected value and solving the resulting linear programming problem. In this paper conditions are given for the equality of the expected value of the objective function for the optimal solution and the value of the objective function for the approximate solution; bounds on these values are also given. In addition, the relation between this problem and a related problem, where one makes an observation on the “right-hand side” and solves the nonstochastic linear programming problem based on this observation, is discussed.

Detracking America's schools: Equity at zero cost?

Abstract: Schools across the country are ending the practice of grouping students based on ability, in part, because of research indicating that tracking hurts low-ability students without helping students of other ability levels. Using a nationally representative survey conducted by the National Center for Education Statistics, (NCES) we reexamine the impact of tracking on high school student achievement through the estimation of a standard education production function. This approach allows us to control for the possibility that track is correlated with factors such as class size and teacher education. In addition, we address the possibility that there are unobserved student or school characteristics that affect both achievement and track placement. Our results indicate that abolishing tracking in America's schools would have a large positive impact on achievement for students currently in the lower tracks, but that this increase in achievement would come at the expense of students in upper-track classes.

Problem-solving skills and affective expressions as predictors of change in marital satisfaction.

Abstract: Specific skills and affective expressions coded from the problem-solving interactions of 172 newlywed couples were examined in relation to 8-wave, 4-year trajectories of marital satisfaction. Effects varied as a function of whether husbands' versus wives' topics were under discussion and whether husbands' versus wives' satisfaction was predicted, but results indicate that skills, affect, and their statistical interaction account for unique variance in rates of change in marital satisfaction. The interaction between positive affect and negative skills was particularly robust, indicating that (a) low levels of positive affect and high levels of negative skills foreshadowed particularly rapid rates of deterioration and that (b) high levels of positive affect buffered the effects of high levels of negative skills. Findings suggest specific targets for intervention in programs for developing marriages.

Rain scavenging of radioactive particulate matter from the atmosphere

Abstract: On the basis of Langmuir's theory of collection efficiencies, a model is derived to explain the removal of radioactive particulate matter from the atmosphere by rain. In this connection, Langmuir's collection efficiencies are modified to take into account the density of the solid particles, and are adjusted to express the fraction removed from a vertical cylinder of constant diameter. It is assumed that electrostatic effects can be neglected in the presence of ionizing radiation. It is found that direct interaction of raindrops and particles does not account for the efficient removal of material whose diameter is below approximately 1 micron. To explain the removal of these smaller particles, a further mechanism is investigated. This consists of allowing the particles to mix with the water cloud before the rain starts. Small particles that are scavenged by cloud droplets by a process of coagulation are then placed in a position to be more efficiently removed by the rain. Fractions of a given part...