Detecting Directionality in Time Series

Abstract

Directionality can be seen in many stationary time series from various disciplines, but it is overlooked when fitting linear models with Gaussian errors. Moreover, we cannot rely on distinguishing directionality by comparing a plot of a time series in time order with a plot in reverse time order. In general, a statistical measure is required to detect and quantify directionality. There are several quite different qualitative forms of directionality, and we distinguish: rapid rises followed by slow recessions; rapid increases and rapid decreases from the mean followed by slow recovery toward the mean; directionality above or below some threshold; and intermittent directionality. The first objective is to develop a suite of statistical measures that will detect directionality and help classify its nature. The second objective is to demonstrate the potential benefits of detecting directionality. We consider applications from business, environmental science, finance, and medicine. Time series data are collected from many processes, both natural and anthropogenic, by a wide range of organizations, and directionality can easily be monitored as part of routine analysis. We suggest that doing so may provide new insights to the processes.     

HIGH SCHOOL CHOICES AND THE GENDER GAP IN STEM

Women are less likely than men to graduate with a degree in science, technology, engineering, or math (STEM). We use detailed administrative data for a recent cohort of Ontario high school students, combined with data from the province's university admission system, to analyze the sources of this gap. We show that entry to STEM programs is mediated through an index of STEM readiness that depends on end‐of‐high school courses in math and science. Most of the gender gap in STEM entry can be traced to differences in the share of college entrants who are STEM‐ready; only a small share is attributable to differences in the choice of major conditional on readiness. We then use high school course data to decompose the gender gap in STEM readiness into two channels: one reflecting the gap in the fraction of high school students with the necessary prerequisites to enter STEM, the other arising from differences in the overall fractions of females and males who enter university. The gender gap in the fraction of males and females with STEM prerequisites is small. The primary driver of the gap in STEM readiness is the low rate of university entry by nonscience‐oriented males. (JEL I21, 28, I20)     

Finding your way into employment against all odds? Successful job search of refugees in Austria

Labour market entry poses enormous challenges for recently arrived refugees, ranging from language barriers, devaluation of human capital, unfamiliarity with customs of the job search process to outright discrimination. How can refugees overcome these challenges and quickly enter gainful employment? In this paper, we draw on interviews with 26 male and female refugees from Syria, Afghanistan, Iraq and Iran, conducted in 2017 and 2018, who came to Austria in 2015 and 2014 and who have successfully entered employment. We depict refugees’ own perspectives on and strategies for fast job entry and integration. Personal agency and a proactive approach of seeking and seizing opportunities are key for overcoming initial barriers and entering upon positive integration pathways. At the same time, refugees’ personal agency is essential for establishing social ties to the host society, which also play a crucial role in early labour market integration. Finally, institutions of the Austrian labour market (the ‘apprenticeship’-system) interact with refugees’ agency in most intricate ways, both setting up nearly insurmountable barriers but also providing specific opportunities for refugees.     

Predicting Maternal Resolution of Preterm Birth at One Month Corrected Age

Early maternal resolution with preterm birth was assessed at one month corrected age (CA), and potential maternal and infant characteristics that may be associated with early resolution were examined. Fifty‐five mothers of preterm infants (≤34 weeks) participated. Data regarding pregnancy, prenatal risk, delivery, infant's medical risk, maternal well‐being status, and infant's early developmental status were collected. Resolution was examined using the Reaction to Diagnosis Interview (RDI). A total of 38.2% of the mothers were classified as resolved. Only completion of antenatal corticosteroids (ACS) treatment and high prenatal risk significantly predicted maternal resolution. Early maternal resolution of preterm birth is associated with early knowledge regarding the preterm birth.     

Exploring Rotation Placements for Social Work: A Focus on Student and Supervisor Experiences

Increasing demand for social work placements in a climate of decreasing availability has intensified the search for capacity-building models of field education. Rotation placements may be part of the solution, yet little is currently known about how rotations affect the experience of field education in the context of block placements. A study of 128 Master of Social Work (MSW) students and 92 supervisors provided insights into the experience of rotation placements in five Australian hospitals. The study adopted a mixed-methods design using online surveys followed by postplacement interviews over 3 years. The findings show that experiences were mixed. However, there were also some common themes that help inform what might work, for whom, and under what circumstances.