Exploring IDR: A Comparison of Financial Situations and Behaviors Between Those in Traditional Student Loan Repayment and Those in Income-Driven Repayment

This quantitative, exploratory study (N=266) examines: (1) financial differences between those enrolled in student-loan based Traditional and Income-Driven Repayment (IDR) schemes, (2) factors that link to IDR enrollment, and (3) whether IDR correlates to the likelihood of reporting to save zero dollars in savings and retirement and in being a homeowner. Descriptive tests indicated differences in loan and earnings-related measurements, and other financial differences, favoring those in traditional repayment. Logistic regression reporting Marginal Effects suggested enrollment in IDR correlated with student loan debt starting at $60,000 and upward (ME=0.41-0.59) and income (ME=0.52-0.36) - with lower-middle to middle-income earners being most likely enrolled (GAI$25,000-39,9999 and GAI $40,000-54,999). IDR enrollment was also correlated with being married (ME=-0.24), being male (ME=-0.20), and living in an urban cluster (ME=0.25). Furthermore, IDR enrollment correlated with a higher likelihood of claiming to save “zero” dollars per month (ME=0.25) but not with participation in monthly retirement savings or homeownership. Discussion leans on Rational Choice Theory and Permanent Income Hypotheses to explain why individuals choose enrollment into IDR, calling for financial aid practitioners to provide counsel on the decision, and for additional research and caution as IDR is being examined for modification without a strong understanding of borrowers’ situations

Measurement of the Nodal Precession of WASP-33 b via Doppler Tomography

We have analyzed new and archival time series spectra taken six years apart during transits of the hot Jupiter WASP-33 b, and spectroscopically resolved the line profile perturbation caused by the Rossiter-McLaughlin effect. The motion of this line profile perturbation is determined by the path of the planet across the stellar disk, which we show to have changed between the two epochs due to nodal precession of the planetary orbit. We measured rates of change of the impact parameter and the sky-projected spin-orbit misalignment of $db/dt=-0.0228_{-0.0018}^{+0.0050}$ yr$^{-1}$ and $d\lambda/dt=-0.487_{-0.076}^{+0.089}$~$^{\circ}$ yr$^{-1}$, respectively, corresponding to a rate of nodal precession of $d\Omega/dt=0.373_{-0.083}^{+0.031}$~$^{\circ}$ yr$^{-1}$. This is only the second measurement of nodal precession for a confirmed exoplanet transiting a single star. Finally, we used the rate of precession to set limits on the stellar gravitational quadrupole moment of $9.4\times10^{-5}<J_2<6.1\times10^{-4}$.Comment: Published in ApJL. 5 pages, 3 figures. Corrected error in the calculation of J_

TriCheck: Memory Model Verification at the Trisection of Software, Hardware, and ISA

Memory consistency models (MCMs) which govern inter-module interactions in a shared memory system, are a significant, yet often under-appreciated, aspect of system design. MCMs are defined at the various layers of the hardware-software stack, requiring thoroughly verified specifications, compilers, and implementations at the interfaces between layers. Current verification techniques evaluate segments of the system stack in isolation, such as proving compiler mappings from a high-level language (HLL) to an ISA or proving validity of a microarchitectural implementation of an ISA. This paper makes a case for full-stack MCM verification and provides a toolflow, TriCheck, capable of verifying that the HLL, compiler, ISA, and implementation collectively uphold MCM requirements. The work showcases TriCheck's ability to evaluate a proposed ISA MCM in order to ensure that each layer and each mapping is correct and complete. Specifically, we apply TriCheck to the open source RISC-V ISA, seeking to verify accurate, efficient, and legal compilations from C11. We uncover under-specifications and potential inefficiencies in the current RISC-V ISA documentation and identify possible solutions for each. As an example, we find that a RISC-V-compliant microarchitecture allows 144 outcomes forbidden by C11 to be observed out of 1,701 litmus tests examined. Overall, this paper demonstrates the necessity of full-stack verification for detecting MCM-related bugs in the hardware-software stack.Comment: Proceedings of the Twenty-Second International Conference on Architectural Support for Programming Languages and Operating System

Exploring the Relationship of Enrollment in IDR to Borrower Demographics and Financial Outcomes

As federal policymakers consider changes to income-driven repayment (IDR) schemes, research examining the characteristics and financial behaviors of student loan borrowers participating in IDR is necessary. Using the nationally representative Survey of Consumer Finances, we examined the demographics of IDR enrollment. Counter to expectations, low-income borrowers, and borrowers with high debt-to-income ratios are less likely to enroll in IDR. Conditional on having a large amount of debt, married women of color are likely to enroll in IDR programs. Findings concerning IDR participation may be highly sensitive to how groups are defined and what covariates are in models. IDR participation does not predict engagement in other financial behaviors such as retirement savings or homeownership

Another Lesson on Caution in IDR Analysis: Using the 2019 Survey of Consumer Finances to Examine Income-Driven Repayment and Financial Outcomes

We update Collier et al. (2021) by using the Survey of Consumer Finances (SCF) 2019 dataset to explore characteristics of enrollees in Income-Driven Repayment (IDR). SCF 2019 is more likely to include borrowers engaged in REPAYE. Findings support an ongoing need to encourage greater IDR participation for lowest-income borrowers and reinforce greater participation by female borrowers. Again, model specification affects findings regarding IDR enrollment. REPAYE appears to have widened access to IDR by lowering the debt floor for entry. IDR enrollment was correlated with less money in a traditional checking account and a lower chance of engaging in retirement savings

Ecological selectivity of pesticides and application methods

According to David Pimentel, 20 years ago, less than 0.1% of the pesticides applied reached their target pests (Pimentel, 1995). This was partly due to ‘poor’ application methods and partly because of the minuscule amount of pesticide either picked up or consumed by the pest. At the time, Pimentel was describing the application of pesticides mainly by sprays, including aerial spraying, and both pesticide chemistry and application technology have improved since then. However, a considerable proportion of pesticides are still applied as sprays, either to crop foliage or to the soil, and this continues to be a relatively untargeted method of application

How College Enrollment Changed for Kalamazoo Promise Students Between Fall 2019 and Fall 2020

The COVID-19 pandemic greatly reduced the college enrollment rate for students during the Fall 2020 semester. National data show that although enrollment of new students declined overall, it varied substantially by institution type and student characteristics. What national data do not reveal is how certain communities with already high college-going rates responded to the pandemic. We use data from Kalamazoo Public Schools (KPS) and the tuition-free program the Kalamazoo Promise to compare the immediate college enrollment of graduating high school students from the class of 2019 to that of the class of 2020. Overall, immediate college enrollment of KPS graduates declined from 74 percent to 60 percent. These declines were concentrated at two-year institutions among students who were socioeconomically disadvantaged, as well as among Black and Hispanic students. Contrary to national trends, immediate enrollment for KPS graduates at four-year institutions increased, with gains driven primarily (but not entirely) by White students. We present suggestive evidence that the Kalamazoo Promise, and policy decisions at four-year colleges, allowed some students to “trade up” from a two-year to a four-year institution

Cybercrime is (often) boring: maintaining the infrastructure of cybercrime economies

It is generally accepted that the widespread availability of specialist services has helped drive the growth of cybercrime in the past fifteen to twenty years. Individuals and groups involved in cybercrime no longer need to build their own botnet or send their own spam because they can pay others to do these things. What has seldom been remarked upon is the amount of tedious administrative and maintenance work put in by these specialist suppliers. There is much discussion of the technically sophisticated work of developing new strains of malware or identifying zero-day exploits but the mundane nature of the day to day tasks of operating infrastructure has been almost entirely overlooked. Running bulletproof hosting services, herding botnets, or scanning for reflectors to use in a denial of service attack is unglamorous and tedious work, and is little different in character from the activity of legitimate sysadmins. We provide three case studies of specialist services that underpin illicit economies and map out their characteristics using qualitative sociological research involving interviews with infrastructure providers and scraped data from webforums and chat channels. This enables us to identify some of the distinct cultural and economic factors which attend this infrastructural work and to note, in particular, how its boring nature leads to burnout and the withdrawal of services. This leads us to suggest ways in which this new understanding could open novel avenues for the disruption of cybercrime.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC)

You don't know how it feels to be me: an exploration of those who belong to online groups and communities dedicated to student loan debt information dissemination and reform

Student loan debt has become a topic of great economic and social concern. With this debt surpassing $1.2 trillion dollars – a staggering amount by any measure – the anxiety and alarm surrounding this issue cannot be overstated. This research aims to help the general public,scholars, and policymakers more fully understand how this debt affects various financial, social,and political behaviors and beliefs. This sample (n = 293) was collected from individuals who are involved with various online communities that act as a social support system and political activity center for student loan debtors. This sample is unique as at the time of writing this manuscript the researcher is unaware of anyone conducting research on these communities. Findings of this research suggest that there are various differences between those who own$40,000 or less in debt and those who are above $40,000 in debt. This research has uncovered educational attainment differences with those who have less debt having generally earned only a bachelor’s degree whereas those who are more indebted holding master's degrees. Financially, statistical differences are found between yearly gross earnings, monthly savings, percent of monthly income to repay student loan debt, percent of max credit card debt, and FICO score category. Additionally found were differences in reporting to ignore health concerns, in stress levels, and in political behaviors and beliefs. Deeper exploration of these differences suggest that for each group different variables have influenced borrowing, monthly savings, ignoring health, stress levels, and political beliefs and behaviors. Discussion focuses on connections to previous research and explores some of the more unique findings, such as for the more indebted group enrollment in income-based repayment promotes ignoring health concerns. Recommendations and implications focus on the wider contributions to the field and future research suggestions