Essays on Imperfect Competition in the Labor Market

This thesis consists of three chapters on imperfect competition in the labor market. The first chapter (joint with Nikolaj Harmon) explores the relationship between an individual\u27s wages and the quality of her opportunities at other firms (her outside options). To overcome the fact that many factors that shift an individual\u27s outside opportunities also impact her productivity at her current job, we develop a novel identification strategy that generates within-individual (and within-firm-by-occupation) variation in workers\u27 information about their outside options. This strategy, which we implement using linked employer-employee data from Denmark, exploits the fact that individuals often learn about labor market opportunities through their social networks. We find that increases in labor demand at former coworkers\u27 current firms increases an incumbent worker\u27s job-to-job mobility and wage growth. Consistent with theory, larger changes are necessary to induce a job-to-job transition than to induce a wage gain. Tests that exploit within-firm or within-firm-and-occupation variation and tests that exploit different subsets of an individual\u27s former coworkers confirm that the results are not driven by unobserved changes in demand for workers\u27 skills. Finally, we use our reduced form moments to identify a structural search model incorporating both posting and bargaining firms. We find that bargaining is more prevalent among high skilled workers. The second chapter (joint with Oren Danieli) investigates the role that cross-sectional differences in individuals\u27 outside options play in generating between-group wage inequality. We use a two-sided matching model to micro-found a measure of workers\u27 outside options, which we call the Outside Options Index (001). The index is similar to those used in the industrial organization literature to measure concentration (e.g. the Herfindal-Hirschman Index, the HHI). We then use German administrative data to estimate this index and use two sources of quasi-random variation: (1) the introduction of high-speed trains and (2) a standard shift-share instrument to identify the elasticity between our index and wages. When we combine these two ingredients, we find that roughly 1/3 of the gender wage gap in Germany can be explained by differences in options, mostly the result of differences in effective labor market size (commuting costs). The third chapter (joint with Emily Oehlsen) asks whether, in the absence of commuting costs, firms with market power have an incentive to pay women less than men. We use data from a series of experiments at Uber where we offered random subsets of male and female drivers higher wages . Drivers varied both in the size of the wage increase and in whether they could drive for Uber\u27s main competitor, Lyft. These two sources of variation allow us to experimentally identify: (1) Frisch elasticities and (2) firm substitution elasticities. We find that women have Frisch elasticities double those of men on both the intensive and extensive margin. However, unlike the prior literature, we find that women are not less likely to shift between firms in response to changes in relative wages. The results suggest that, at least in the gig economy, firms have little incentive to wage discriminate between men and women based on their labor supply choices

Readying Extension for the Systematic Analysis of Large Qualitative Data Sets

Land-grant Extension institutions face increasing expectations to use data to communicate value and drive program and organizational development. In this article, we introduce the University of Wisconsin–Extension Data Jam Initiative, an integrated qualitative software, methods, and data analysis curriculum. The Data Jam Initiative is an evaluation capacity building framework for collaborative, mentorship-based analysis sessions across an institution and across disciplines. Through sharing exemplar applications of this curriculum, we illustrate how the Data Jam Initiative prepares Extension institutions for using qualitative data in service of communication to stakeholders, program development, and organizational growth

Service provider boundaries in competitive markets: the case of the logistics industry

The study empirically investigates service provider firms’ attempts to move to higher value added market segments in competitive and fragmented markets; using logistics services as a context. Novelty is added by taking the provider not the customer or outsourcing actor perspective, common to current third-party logistics perspectives. Data were collected in the form of semi-structured interviews with management at various provider firms. The interview guide was based on theoretical constructs regarding tangible and intangible capabilities (RBV) as well as constructs related to governance and integration (TCE). Unlike customer focused studies, this study is able to identify what distinguishes the rare successful boundary crossing attempts that lead to a more profitable market position. The key finding which contradicts studies based on the customer/outsourcing actor perspective, is that a switch from a highly commoditized market position to a higher margin position is only possible, if relationships and network capabilities are leveraged, regardless of the assets and physical resources available to the firm. The presentation of service boundaries as both dynamic and fluid and the use of RBV are contributions, building on existing theory, illustrating why providers of commoditized services cannot escape from low-margin, competitive market positions simply by acquiring tangible assets

Second Harmonic Generation from Phononic Epsilon-Near-Zero Berreman Modes in Ultrathin Polar Crystal Films

Immense optical field enhancement was predicted to occur for the Berreman mode in ultrathin films at frequencies in the vicinity of epsilon near zero (ENZ). Here, we report the first experimental proof of this prediction in the mid-infrared by probing the resonantly enhanced second harmonic generation (SHG) at the longitudinal optic phonon frequency from a deeply subwavelength-thin aluminum nitride (AlN) film. Employing a transfer matrix formalism, we show that the field enhancement is completely localized inside the AlN layer, revealing that the observed SHG signal of the Berreman mode is solely generated in the AlN film. Our results demonstrate that ENZ Berreman modes in intrinsically low-loss polar dielectric crystals constitute a promising platform for nonlinear nanophotonic applications

Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569

Photometric and spectroscopic analyses have shown that the Galactic bulge cluster Terzan 5 hosts several populations with different metallicities and ages that manifest as a double red horizontal branch (HB). A recent investigation of the massive bulge cluster NGC 6569 revealed a similar, though less extended, HB luminosity split, but little is known about the cluster's detailed chemical composition. Therefore, we have used high-resolution spectra from the Magellan-M2FS and VLT-FLAMES spectrographs to investigate the chemical compositions and radial velocity distributions of red giant branch and HB stars in NGC 6569. We found the cluster to have a mean heliocentric radial velocity of -48.8 km/s (sigma = 5.3 km/s; 148 stars) and a mean [Fe/H] =-0.87 dex (19 stars), but the cluster's 0.05 dex [Fe/H] dispersion precludes a significant metallicity spread. NGC 6569 exhibits light- and heavy-element distributions that are common among old bulge/inner Galaxy globular clusters, including clear (anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data suggest that NGC 6569 may be composed of at least two distinct populations, and the cluster's low mean [La/Eu] = -0.11 dex indicates significant pollution with r-process material. We confirm that both HBs contain cluster members, but metallicity and light-element variations are largely ruled out as sources for the luminosity difference. However, He mass fraction differences as small as delta Y ~ 0.02 cannot be ruled out and may be sufficient to reproduce the double HB.Comment: 72 pages, 14 figures, 8 tables; published in The Astronomical Journal; electronic versions of all tables are available in the published versio

A Chemical Composition Survey of the Iron-Complex Globular Cluster NGC 6273 (M 19)

Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been recognized as a member of this "iron-complex" cluster class, and we provide here a chemical and kinematic analysis of > 300 red giant branch (RGB) and asymptotic giant branch (AGB) member stars using high resolution spectra obtained with the Magellan-M2FS and VLT-FLAMES instruments. Multiple lines of evidence indicate that NGC 6273 possesses an intrinsic metallicity spread that ranges from about [Fe/H] = -2 to -1 dex, and may include at least three populations with different [Fe/H] values. The three populations identified here contain separate first (Na/Al-poor) and second (Na/Al-rich) generation stars, but a Mg-Al anti-correlation may only be present in stars with [Fe/H] > -1.65. The strong correlation between [La/Eu] and [Fe/H] suggests that the s-process must have dominated the heavy element enrichment at higher metallicities. A small group of stars with low [alpha/Fe] is identified and may have been accreted from a former surrounding field star population. The cluster's large abundance variations are coupled with a complex, extended, and multimodal blue horizontal branch (HB). The HB morphology and chemical abundances suggest that NGC 6273 may have an origin that is similar to omega Cen and M 54.Comment: Accepted for Publication in The Astrophysical Journal; 50 pages; 18 figures; 8 tables; higher resolution figures are available upon request or in the published journal articl

Identification of sex hormone-binding globulin in the human hypothalamus

Gonadal steroids are known to influence hypothalamic functions through both genomic and non-genomic pathways. Sex hormone-binding globulin ( SHBG) may act by a non-genomic mechanism independent of classical steroid receptors. Here we describe the immunocytochemical mapping of SHBG-containing neurons and nerve fibers in the human hypothalamus and infundibulum. Mass spectrometry and Western blot analysis were also used to characterize the biochemical characteristics of SHBG in the hypothalamus and cerebrospinal fluid (CSF) of humans. SHBG-immunoreactive neurons were observed in the supraoptic nucleus, the suprachiasmatic nucleus, the bed nucleus of the stria terminalis, paraventricular nucleus, arcuate nucleus, the perifornical region and the medial preoptic area in human brains. There were SHBG-immunoreactive axons in the median eminence and the infundibulum. A partial colocalization with oxytocin could be observed in the posterior pituitary lobe in consecutive semithin sections. We also found strong immunoreactivity for SHBG in epithelial cells of the choroid plexus and in a portion of the ependymal cells lining the third ventricle. Mass spectrometry showed that affinity-purified SHBG from the hypothalamus and choroid plexus is structurally similar to the SHBG identified in the CSF. The multiple localizations of SHBG suggest neurohypophyseal and neuroendocrine functions. The biochemical data suggest that CSF SHBG is of brain rather than blood origin. Copyright (c) 2005 S. Karger AG, Base