A large interdisciplinary body of research on human judgment and decision making documents systematic deviations between prescriptive decision models (i.e., how individuals should behave) and ...descriptive decision models (i.e., how individuals actually behave). One canonical example is the loss-gain framing effect on risk preferences: the robust tendency for risk preferences to shift depending on whether outcomes are described as losses or gains. Traditionally, researchers argue that decision makers should always be immune to loss-gain framing effects. We present three preregistered experiments (N = 1,954) that qualify this prescription. We predict and find that while third-party observers penalize decision makers who make risk-averse (vs. risk-seeking) choices when choice outcomes are framed as losses, this result reverses when outcomes are framed as gains. This reversal holds across five social perceptions, three decision contexts, two sample populations of United States adults, and with financial stakes. This pattern is driven by the fact that observers themselves fall victim to framing effects and socially derogate (and financially punish) decision makers who disagree. Given that individuals often care deeply about their reputation, our results challenge the long-standing prescription that they should always be immune to framing effects. The results extend understanding not only for decision making under risk, but also for a range of behavioral tendencies long considered irrational biases. Such understanding may ultimately reveal not only why such biases are so persistent but also novel interventions: our results suggest a necessary focus on social and organizational norms.
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The ability to speak and understand a host country’s primary language is strongly associated with measures of immigrant integration. We estimate the causal effects of English language training for ...adult immigrants on participants’ civic and economic outcomes using randomized enrollment lotteries from a public adult education program in Massachusetts. Participation doubles voter participation and increases annual earnings by $2,400 (56 percent). Increased tax revenue from earnings gains cover program costs over time, generating a 6 percent return for taxpayers. Ours is the first randomized evaluation of adult English language training as a standalone intervention in the United States. (JEL D72, H75, I21, I26, J15, J24, J31)
Recent advances in Fused Filament Fabrication (FFF) include large material deposition rates and the addition of chopped carbon fibers to the filament feedstock. During processing, the flow field ...within the polymer melt orients the fiber suspension, which is important to quantify as the underlying fiber orientation influences the mechanical and thermal properties. This paper investigates the correlation between processing conditions and the resulting locally varying thermal-structural properties that dictate both the final part performance and part dimensionality. The flow domain includes both the confined and unconfined flow indicative of the extruder nozzle within the FFF deposition process. The resulting orientation is obtained through two different isotropic rotary diffusion models, the model by Folgar and Tucker and that of Wang et al., and a comparison is made to demonstrate the sensitivity of the deposited bead’s spatially varying orientation as well as the final processed part’s thermal-structural performance. The results indicate the sensitivity of the final part behavior is quite sensitive to the choice of the slowness parameter in the Wang et al. model. Results also show the need, albeit less than that of the choice of fiber interaction model, to include the extrudate swell and deposition within the flow domain.
Although it is well known that certain charter schools dramatically increase students' standardized test scores, there is considerably less evidence that these human capital gains persist into ...adulthood. To address this matter, we match three years of lottery data from a high-performing charter high school to administrative college enrollment records and estimate the effect of winning an admissions lottery on college matriculation, quality, and persistence. Seven to nine years after the lottery, we find that lottery winners are 10.0 percentage points more likely to attend college and 9.5 percentage points more likely to enroll for at least four semesters. Unlike previous studies, our estimates are powerful enough to uncover improvements on the extensive margin of college attendance (enrolling in any college), the intensive margin (persistence of attendance), and the quality margin (enrollment at selective, four-year institutions). We conclude by providing nonexperimental evidence that more recent cohorts at other campuses in the network increased enrollment at a similar rate.
The viability of Fused Filament Fabrication (FFF) as an Additive Manufacturing (AM) method is improved by including discrete carbon fibers in the polymer feedstock. The resulting carbon fiber polymer ...composite enhances mechanical and thermal properties, where improvements are directly related to the orientation of the carbon fibers within the extruded polymer composite. Fiber orientation in the polymer melt is affected by the flow field which is defined by the melt flow geometry including flow in the nozzle convergence and extrudate swell. This paper presents a computational approach for modeling the polymer melt flow and the associated effects of nozzle geometry and extrudate swell on fiber orientation in the extruded polymer. The finite element method is used to evaluate Stokes flow in the axisymmetric flow field of an FFF nozzle. Fiber orientation tensors are calculated throughout the fluid domain using the Orthotropic Fitted Closure and the Folgar-Tucker isotropic fiber interaction model. The radial and axial modulus of the extruded polymer is then calculated from fiber orientation tensors within the composite at the nozzle exit. Fiber orientation along the extrudate axis is shown to increase due to elongation flow within the nozzle convergence zone and decrease in the extrudate swell such that the modulus of elasticity of the extruded polymer is moderately affected by extrudate swell and substantially affected by the nozzle geometry.
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The rapid transition of the Fused Filament Fabrication (FFF) Additive Manufacturing (AM) process from small scale prototype models to large scale polymer deposition has been driven, in part, by the ...addition of short carbon fibers to the polymer feedstock. The addition of short carbon fibers improves both the mechanical and thermal properties of the printed beads. The improvements to the anisotropic mechanical and thermal properties of the polymer feedstock are dependent on the spatially varying orientation of short carbon fibers which is itself a function of the velocity gradients in the flow field throughout the nozzle and in the extrudate during deposition flow. This paper presents a computational approach for simulating the deposition flow that occurs in the Large Area Additive Manufacturing (LAAM) process and the effects on the final short fiber orientation state in the deposited polymer bead and the resulting bead mechanical and thermal properties. The finite element method is used to evaluate Stokes flow for a two-dimensional planar flow field within a Strangpresse Model 19 LAAM polymer deposition nozzle. A shape optimization method is employed to compute the shape of the polymer melt flow free surface below the nozzle exit as the bead is deposited on a moving print platform. Three nozzle configurations are considered in this study. Fiber orientation tensors are calculated throughout the fluid domain using the Folgar-Tucker fiber interaction model. The effective bulk mechanical properties, specifically the longitudinal and transverse moduli, and the coefficient of thermal expansion, are also calculated for the deposited bead based on the spatially varying fiber orientation tensors. Fiber orientation is found to be highly aligned along the deposition direction of the resulting bead and the computed properties through the thickness of the bead are found to be affected by nozzle height during deposition.
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7.
Raising More Than Test Scores Davis, Matthew; Heller, Blake
Education next,
12/2017, Volume:
17, Issue:
1
Journal Article
Peer reviewed
Open access
...to our knowledge, our results are the first to demonstrate conclusively that a high school intervention can simultaneously improve overall college enrollment, persistence, and quality. ...we ...demonstrate the effectiveness of an intervention that occurs relatively late in students' academic lives.
Do "no excuses" charter high schools merely help students succeed on standardized tests? Are their students more likely to succeed after they leave school behind? Is it test prep, or true learning? ...Little prior research is available on this question. Although there is a robust positive correlation between test performance and college enrollment, there is little existing evidence as to whether schools that increase test scores the most also help their students succeed at the next level. To shed light on these questions, Mathew Davis and Blake Heller studied Noble Street College Prep, a high-performing no-excuses charter high school in Chicago where admission is granted via randomized lottery. Student records were analyzed to estimate the effect of attending Noble on college enrollment, persistence, and quality, using success in postsecondary studies as a proxy for success in young adulthood. As no-excuses charter schools continue to expand, it is critical to understand whether the short-term academic gains they typically produce translate into long-term improvements in their students' quality of life. The authors of this article believe their findings present the strongest evidence to date of long-lasting academic benefits, and should be a cause for cautious optimism. They see three elements of this analysis that should be of interest: (1) Noble's educational model is broadly consistent with the practices of high-performing charter schools, and their secondary analysis suggests that scaling and reproducing these results is feasible. The estimated effects are large, persistent, and not driven by any particular subgroup of students; (2) The authors write that to the best of their knowledge, their results are the first to demonstrate conclusively that a high school intervention can simultaneously improve overall college enrollment, persistence, and quality; and (3) The authors contend that they demonstrate the effectiveness of an intervention that occurs relatively late in students' academic lives. While much of the public conversation around school improvement focuses on early childhood and the elementary years, in an effort to prevent or lessen inequitable outcomes for poor children, the authors believe it is clear that efforts such as Noble's intensive academic program which starts in 9th grade are never too late.
This dissertation consists of three essays examining public education's role in the formation of human capital from high school through adulthood. I use quasi-experimental methods assess the returns ...to three types of targeted educational interventions that develop the skills of adults and older children: (1) providing English language training to adult immigrants and refugees with limited English proficiency, (2) credentialing adult dropouts whose test performance signals they are academically prepared for college-level coursework, and (3) offering disadvantaged high school students the chance to enroll in academically rigorous public charter schools that ascribe to a "No-excuses" educational philosophy.After decades of research on job training and adult skill formation, labor economists have increasingly neglected programs of research focused on public investments in human capital for low-skilled adults and adolescents in favor of interventions that occur earlier in the life cycle. The principle underlying the "Heckman Equation," that "early investments targeted toward disadvantaged children have much higher returns than later interventions" has quickly become accepted wisdom, driving human capital research, funding, and attention toward early childhood and K-5 education (Heckman, 2006, 2012a).While Heckman’s conclusions about complementarities in educational investments and diminishing marginal returns of human capital investments over an individual’s life cycle hold true on average, it is not clear that current, low levels of public investment in human capital interventions that begin in late adolescence or adulthood are efficient. In fact, theory suggests that interventions that target adults and older children with latent human capital may have especially high returns (Borjas, 1989; Becker, 1994). This dissertation is organized around three populations that may benefit from such interventions: adult immigrants who do not speak English fluently, high-performing uncredentialled adults and high school dropouts, and underserved high school students in low-income communities.Chapter 1 (co-authored with Kirsten Slungaard Mumma) leverages randomized lotteries for access to English for Speakers of Other Languages (ESOL) services to estimate the causal effect of being offered a chance to attend ESOL classes on measures of civic engagement and economic integration for adult immigrants in Framingham, Massachusetts. We find that attending ESOL classes more than doubles rates of voter registration and substantially increases annual employer-reported earnings. Chapter 2 describes the national population of "college-ready" GED® testers and uses quasi-experimental variation in eligibility for GED® college readiness designations to examine whether being designated as "college-ready" makes marginally qualifying students more likely to enroll and persist in college. I find no evidence that GED® college readiness benchmarks promote better college outcomes, but in the absence of more detailed test score information these designations offer a simple heuristic to predict short-run college enrollment and persistence. Chapter 3 (co-authored with Matthew Davis) draws on another set of randomized lotteries to measure the effects of attending a so-called "No Excuses" charter high school network in Chicago on students' post-secondary enrollment and success. We find that lottery winners are more likely to matriculate to college, enroll in more selective institutions, and attend for longer than their peers who entered but did not win an enrollment lottery. Assessing the impacts of these three distinct interventions advances knowledge about which types of late human capital investments have high or low returns and why, helping policymakers better identify and create opportunities to efficiently invest in adults' and adolescents' human capital.
Can a school or district improve student achievement simply by switching to a higher‐quality textbook or curriculum? We conducted the first multi‐textbook, multi‐state effort to estimate textbook ...efficacy following widespread adoption of the Common Core State Standards (CCSS) and associated changes in the textbook market. Pooling textbook adoption and student test score data across six geographically and demographically diverse U.S. states, we found little evidence of differences in average achievement gains for schools using different math textbooks. We found some evidence of greater variation in achievement gains among schools using pre‐CCSS editions, which may have been more varied in their content than post‐CCSS editions because they were written for a broader set of standards. We also found greater variation among schools that had more exposure to a given text. However, these differences were small. Despite considerable interest and attention to textbooks as a low‐cost, “silver bullet” intervention for improving student outcomes, we conclude that the adoption of a new textbook or set of curriculum materials, on its own, is unlikely to achieve this goal.
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