1,068 research outputs found
Policy Issues in the Economics of Education: Lessons from Michigan
In this dissertation, I apply administrative data from Michigan's public schools to address crucial policy questions in the economics of education. In Chapter I, I shed light on the persistent effects of attending high-quality high schools by creating a value-added model that isolates each high school's effect on students' test scores, then matching the results to students' college transcripts to determine the relationship between high-school value added and first-year college grades. I find that students who attend high schools with one standard deviation higher value added receive first-year grades about 0.09 grade points higher than their otherwise-identical counterparts. These gains in college are not driven solely by math and English, but are evenly distributed across subjects. This result is robust to adjustments for a number of potential biases that arise throughout the process, including selection into high schools and selection into college attendance. Overall, I find evidence against some of
the more skeptical interpretations of test-score improvement, such as the claim that schools "teach to the test" or the concern that the content tested on standardized exams is not relevant to future learning. Human capital theory suggests that when students would graduate into a weak labor market, the opportunity cost of schooling declines, and they should instead invest in themselves and get more education. However, this assumes that they have no borrowing constraints; if students are credit-constrained and their families are hurt by the struggling labor market, then their educational options may actually diminish as they are less able to pay for college.
In Chapter II, I determine which of these effects predominates empirically using data on plant closings and mass layoffs from the Worker Adjustment and Retraining Notification ("WARN") Act, examining the impact of exposure to job losses during the senior year of high school on whether and where students attend college. A 1-standard deviation increase in per-capita job losses is associated with a small but statistically-significant 0.2-percentage point
increase in the probability of attending college, driven entirely by attendance at community colleges. This result supports the argument that the opportunity cost effect dominates, as any movement out of college as a result of credit constraints and firsthand exposure to job losses is comparatively small.
Having access to an effective and experienced teacher can make a crucial difference in a student's academic achievement. In Chapter III, written with Kolby Gadd, I examine the factors that predict whether teachers will stay in their first jobs or leave for opportunities elsewhere, and then study how students perform after teachers leave, looking both at teacher turnover in general and at teacher departures for particular destinations such as new districts or the private sector. In a multinomial logit framework in which we examine each teacher's employment status in his or her fifth year, we find that the characteristics that predict departures most consistently are the fraction of Black students in the teacher's first school, the fraction of economically-disadvantaged students in the teacher's first school, the teacher's first job being in special education, and the teacher's first school being a charter. Turning to how student achievement changes in the wake of teacher turnover, we find a modest decline in test scores after teacher exits, driven by students in schools that lost teachers to other full-time teaching positions, both within and across districts.PHDEconomicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145876/1/danieldh_1.pd
Forage Potential of Seasonal Wetlands
Investigations on aspects of seasonal wetland forage potential were conducted in eastern South Dakota. The quantity and quality of the standing crop of vegetation in 6 seasonal wetland communities were assessed at the end of the growing season in 1983 and in 2 seasonal-wetland-dominated basins and their associated uplands (native mixed-grass prairie) over the growing season in 1985. Crude protein (CP), ash, detergent fiber, and in vitro digestible dry matter (IVDDM) values were measured on the above-ground material of whitetop [Scolochloas festucacea (Willd.) Link], slough sedge (Carex atherodes Spreng.), burred (Spargnaium eurycarpum Engelm.), and smartweed (Polygonum amphibium L. var. emersum Michx.) at intervals during the growing seasons of 1984 and 1985. Concurrent measurements of the total nonstructural carbohydrate (TNC) content of below-ground material of these 4 species were also made. An additional 27 species were collected during the summer season of 1984 and 1985 for CP, ash, and IVDDM analyses. Season-long comparisons of wetlands and uplands show that, on an area basis, seasonal-wetland-dominated basins produce higher standing crops of forage than uplands in a native mixed-grass prairie situation. The large late-season standing crop estimates (679 to 1146 g·m‾²) in 6 seasonal wetlands, as well as values in the literature, suggest that most seasonal wetlands probably do yield higher standing crops (on a single cutting basis) than native mixed-grass prairie or cultivated cool-season grasses. However, the digestibility of the dominant wetland forages is lower, on the average, than native upland forage. Several subordinate forb species were found to have high IVDDM and CP values during mid-summer and may be potential candidates for a wetland forage breeding program. Seasonal-wetland-dominated basins should be utilized early in the growing season to optimize forage quality. CP and IVDDM contents of whitetop and slough sedge were comparable to most grasses at similar phenological stages. At mid-summer, however, the nutritional quality of these 2 species is low and would make a hay adequate only as a base roughage. Whitetop nutritional quality is very poor during the latter portion of the growing season, while the quality of slough sedge is maintained at an adequate level for a longer period. TNC reserves in below-ground material of these 2 species are lowest during the approximate periods of tillering and flowering (early June). Utilization at seed-fill for whitetop and just post-seed- fill for slough sedge will avoid the period of low TNC reserves and yet yield an acceptable quality forage. Burreed, on the other hand, is a species that may be considered for control in seasonal wetlands. The TNC content of below-ground material of burred is at its lowest near the onset of flowering. Therefore, control measures should be implemented at that time. If utilized early in the growing season, seasonal wetlands are capable of producing some good quality forages. If utilized in the latter part of the growing season, forage quality may be low but yields are high. With appropriate supplementation, these forages could be used as roughages in domestic livestock rations. Utilization of wetlands for forage production is a use more compatible with other wetland functions than is the artificial draining of them and planning to annual crops
INTERACTIONS BETWEEN THE SHORT-TAILED SHREW, BLARINA BREVICAUDA, AND THE MEADOW VOLE, MICROTUS PENNSYLVANICUS
Breeding Waterfowl Use of Intermittent Streams, McHenry County, North Dakota
Thirty-three 425 m segments of 4 intermittent streams in north central North Dakota were censured for breeding pairs of waterfowl in 1977 and 1978. Pair count data were available for 1976. Emphasis of this study was placed on the narrow meandering portions of the streams. High dabbling duck (Anas spp.) densities were observed in 1977 and 1978; 6.11 pairs per ha and 5.60 pairs per ha, respectively, for the first census of each year. Accepting blue-winged teal (A. discors), numbers of dabbler pairs were similar in 1976 and 1978. Dry conditions in 1977 caused lower numbers of all species of dabblers except gadwalls (A. strepera). Most pothole wetlands in the immediate area were wet in 1976 and dry in 1977 and 1978. Multiple regression analysis was used to analyze some of the factors which influenced pair use of the narrow portions of the streams. Height of emergent vegetation and growing crops \u3e1.5 dm tall were negatively associated with blue-winged teal pairs while hectares of idle l and percent coverage of submersed vegetation were positively associated. Pasture \u3e1.5 dm tall was positively associated with gadwall pairs and was the most important variable in 2 of 3 analyses. Shoreline/surface area ratio, number of Class IV wetlands, percent bare shoreline, and shoreline distance were negatively associated and surface area of water was positively associated with gadwall pairs. Mallard (A. platyrhynchos) pairs were positively associated with shoreline distance and pasture \u3e1.5 dm tall, and negatively associated with mulched stubble \u3c1.5 dm tall and surface area of water off the segments. Shoreline distance was the most important variable in each of two analyses for mallards. It was concluded that these streams were excellent habitat for breeding pairs of dabbling ducks. Stream channelization would severely degrade the waterfowl habitat provided by these streams
Evaluating Effects of Tax Preferences on Health Care Spending and Federal Revenues
In this paper, we calculate the consequences for health spending and federal revenues of an above-the-line deduction for out-of-pocket health spending. We show how the response of spending to this expansion in the tax preference can be specified as a function of a small number of behavioral parameters that have been estimated in the existing literature. We compare our estimates to those from other researchers. And, we use our analysis to derive some implications for tax policy toward HSAs.
New Constraints on the Composition of Jupiter from Galileo Measurements and Interior Models
Using the helium abundance measured by Galileo in the atmosphere of Jupiter
and interior models reproducing the observed external gravitational field, we
derive new constraints on the composition and structure of the planet. We
conclude that, except for helium which must be more abundant in the metallic
interior than in the molecular envelope, Jupiter could be homogeneous (no core)
or could have a central dense core up to 12 Earth masses. The mass fraction of
heavy elements is less than 7.5 times the solar value in the metallic envelope
and between 1 and 7.2 times solar in the molecular envelope. The total amount
of elements other than hydrogen and helium in the planet is between 11 and 45
Earth masses.Comment: 15 pages, 2 figures (1 color
Precious Metals And Retirement Portfolio Survival Rates
Recent gains in the value of gold bullion in the presence of declines in the stock and corporate bond markets suggest that retired investors may benefit from holdings of precious metals. Because of the comparative liquidity and economy of holding mutual fund shares, we examine the effect of an optimal allocation of precious metals funds shares on portfolio survival rates through payout periods of 15, 20, 25, 30, and 35 years using returns data from September 1988 through December 2008. Since most of the higher withdrawal rates that are supported by precious metals funds are ill-advised, adding precious metals fund shares to a conventional stocks and bonds portfolio does not appear to benefit most retired investors. The findings do support greater allocations to bonds rather than stocks
Brueckner-Goldstone perturbation theory for the half-filled Hubbard model in infinite dimensions
We use Brueckner-Goldstone perturbation theory to calculate the ground-state
energy of the half-filled Hubbard model in infinite dimensions up to fourth
order in the Hubbard interaction. We obtain the momentum distribution as a
functional derivative of the ground-state energy with respect to the bare
dispersion relation. The resulting expressions agree with those from
Rayleigh-Schroedinger perturbation theory. Our results for the momentum
distribution and the quasi-particle weight agree very well with those obtained
earlier from Feynman-Dyson perturbation theory for the single-particle
self-energy. We give the correct fourth-order coefficient in the ground-state
energy which was not calculated accurately enough from Feynman-Dyson theory due
to the insufficient accuracy of the data for the self-energy, and find a good
agreement with recent estimates from Quantum Monte-Carlo calculations.Comment: 15 pages, 8 fugures, submitted to JSTA
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