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The Volatility Advantages of Large Labor Markets
No full textFirms' labor demand is more volatile in larger cities. We propose and test a novel explanation for this finding. Faster hiring conditions attract productive firms with more volatile activity to denser locations where they can swiftly downsize or expand. We estimate a model of firm location choice using French data and show that (i) firm volatility is almost as predictive of location choice as productivity; (ii) both dimensions reinforce each other. This mechanism reduces the productivity--density gradient among volatile firms. Imperfectly correlated firm-level shocks, combined with higher operating costs induced by density, generate matching economies
Recommendations for the use of next-generation sequencing (NGS) for patients with advanced cancer in 2024: a report from the ESMO Precision Medicine Working Group
No full textInternational audienceBackground: Advancements in the field of precision medicine have prompted the European Society for Medical Oncology (ESMO) Precision Medicine Working Group to update the recommendations for the use of tumour next-generation sequencing (NGS) for patients with advanced cancers in routine practice.Methods: The group discussed the clinical impact of tumour NGS in guiding treatment decision using the ESMO Scale for Clinical Actionability of molecular Targets (ESCAT) considering cost-effectiveness and accessibility.Results: As for 2020 recommendations, ESMO recommends running tumour NGS in advanced non-squamous non-small-cell lung cancer, prostate cancer, colorectal cancer, cholangiocarcinoma, and ovarian cancer. Moreover, it is recommended to carry out tumour NGS in clinical research centres and under specific circumstances discussed with patients. In this updated report, the consensus within the group has led to an expansion of the recommendations to encompass patients with advanced breast cancer and rare tumours such as gastrointestinal stromal tumours, sarcoma, thyroid cancer, and cancer of unknown primary. Finally, ESMO recommends carrying out tumour NGS to detect tumour-agnostic alterations in patients with metastatic cancers where access to matched therapies is available.Conclusion: Tumour NGS is increasingly expanding its scope and application within oncology with the aim of enhancing the efficacy of precision medicine for patients with cancer
Collaboratively adding context to social media posts reduces the sharing of false news.
No full textWe build a novel database of around 285,000 notes from the Twitter CommunityNotes program to analyze the causal influence of appending contextual information to potentially misleading posts on their dissemination. Employing a difference in difference design, our findings reveal that adding context below a tweet reduces the number of retweets by almost half. A significant, albeit smaller, effect is observed when focusing on the number of replies or quotes. Community Notes also increase by 80% the probability that a tweet is deleted by its creator. The post-treatment impact is substantial, but the overall effect on tweet virality is contingent upon the timing of the contextual information’s publication. Our research concludes that, although crowdsourced fact-checking is effective, its current speed may not be adequate to substantially reduce the dissemination of misleading information on social media
Confidence, consensus and aggregation
No full textThis paper develops and defends a new approach to belief aggregation, involving confidence in beliefs. It is axiomatically characterised by a variant of the Pareto condition that enjoins respecting consensuses borne of compromise. Confidence aggregation generalises standard probability aggregation rules—such as linear pooling— whilst avoiding the spurious unanimity issues that have plagued them. It generates the first family of probability aggregation rules that can faithfully accommodate within-person expertise diversity, hence resolving a longstanding challenge. It is dynamically rational, insofar as it commutes with update. Finally, it recovers as special cases both Bayesian and non-Bayesian approaches to model misspecification
RGCCA for Structural Equation Modeling with Latent and Emergent Variables
No full textInternational audienceIn this work, we show how to use Regularized Generalized Canonical Correlation Analysis (RGCCA) in structural equation modeling with latent and/or emergent variables. This new approach produces consistent and asymptotically normal estimators of the parameters. RGCCA relies on a well-grounded optimization problem and the global convergence of the algorithm used to solve this problem is guaranteed. We also propose a maximum likelihood (ML) estimation method for estimating the parameters of the model. RGCCA and ML are evaluated in a Monte Carlo simulation and lead to similar results. RGCCA and ML are also compared on the ECSI data for the mobile phone industry and produce very close results
Some Seem to Know: Banks’ Lending Decisions After Activist Short Sellers’ Attacks
No full textActivist short sellers publicly disseminate influential negative information about attacked firms. While equity investors strongly react to these reports, it is unclear if lending banks learn from the information released by short sellers. We examine whether and how activist short sellers’ attacks relate to banks’ lending activities. As far as existing loans are concerned, we find no evidence that existing loan agreements are more likely to be renegotiated following allegations by activist short sellers. We find, however, that in the cross-section, this null-average result on renegotiation is explained by disparate, countervailing bank behaviors: some banks hitherto adopted non-renegotiation risk-mitigation measures (such as imposing restrictive covenants) and, as such, were less likely to renegotiate loans following short sellers’ attacks, whereas other banks did not take such actions and, as such, had stronger incentives to renegotiate loans following the attacks. As regards new loans, we find, on average, that banks increase loan pricing following activist short sellers’ allegations (even after controlling for ex-post changes in credit risk). We interpret loan pricing results not explained by ex-post changes in credit risk as rent extraction by banks. Overall, our findings indicate that: (i) some banks seem not to learn from activist short sellers, whereas others seem to; and (ii) banks can also exploit short sellers’ attacks as an opportunity to extract value from attacked firms seeking new loans. This study contributes to our understanding of the information role of activist short sellers relative to other informed market part
Sponsorship Funding in Open-Source Software: Effort Reallocation and Spillover Effects in Knowledge-Sharing Ecosystems
No full textThis study investigates the effects of sponsorship-based funding on open-source software contributors within a knowledge-sharing ecosystem. Specifically, we examine the influence of sponsorship on contributors' activities on the host platform, where funding is received, as well as on a complementary platform without funding. While it is anticipated that sponsorship would increase the overall effort on the host platform, the reallocation of effort between different types of contribution activities (i.e., knowledge creation and maintenance) on the host platform, as well as its spillover effects on other complementary platforms, remain unclear. To address these questions, we analyze the impact of GitHub's sponsorship-funding feature introduced in 2019 on the contribution behavior of the contributors who are listed for the funding. Our methodology involves identifying contributors active on both the host platform (GitHub or GH) and the complementary platform (Stack Overflow or SO) and collecting contributor-level data from both platforms. Using a difference-in-differences estimation framework, we find that a contributor's sponsorship listing on GH leads to an effort reallocation between contribution activities on GH, specifically increasing maintenance-related activities (i.e., reviews of pull requests) while leaving knowledge creation (i.e., pull requests) unaffected. Furthermore, we find evidence of an effort distortion effect that leads to a negative spillover to their contributions on SO, and an effort mirroring effect where contributors listed for sponsorship shift their efforts toward knowledge-maintenance activities, akin to those seen in the host platforms. We discuss the significant implications of these findings
Energy Labels, House Prices, and Efficiency Misreporting
No full textWhat are the implications of the use of discrete energy efficiency labels in the housing market? Using public administrative data from France, where properties are evaluated on a scale from A to G, we show that house prices drop — but time on the market jumps — discontinuously when energy consumption crosses the boundary to a lower rating. These results suggest that, when searching for a home, households form consideration sets excluding properties with energy labels that are considered too unfavorable. We also document substantial bunching of energy performance estimates just below the relevant cut-off values. This pattern appears to be driven by intentional misreporting of properties’ energy efficiency by certified technicians. However, we estimate that the average under-reporting by marginal bunching technicians is relatively small in economic terms, namely 0.7–1.9% of the relevant energy consumption threshold value
Stars in their Constellations: Great Person or Great Team?
No full textWhile much attention is accorded to Star performers, this paper considers the extent to which stars, themselves, benefit from the contribution of their collaborators’ (the constellation). By considering stars, constellations, and synergies between them, we address a key question: To what extent is collaboration performance driven by the great individual or by great constellations? We introduce a novel approach that employs a matching model to uncover the complementarities driving collaboration formation. We use formal value-capture theory to estimate the relative contribution of stars and constellations to joint value creation. Analyzing a sample of academic research collaborations, we document that stars’ relative contribution exceeds their constellations’ contribution in less than 15% of collaborations, while constellations provide a greater relative contribution in 9%. In most collaborations, neither party dominates: innovation is a collective endeavor driven equally by the star and the constellation. Joint value creation and relative contribution are explained by the subtle interplay between complementarities in joint work and the substitutability of collaborative parties in the market. Joint value creation increases with the strength of complementarities between parties in a match. Relative value creation, and hence dominance, increases with the substitutability of one’s collaborative partner. Interestingly, joint value creation is greatest in collaborations where both stars and constellations offer bundles of rare attributes and where neither the star nor the constellation dominates
Gaia Data Release 3: Reflectance spectra of Solar System small bodies
No full text30 pages, 26 figuresInternational audienceContext. The Gaia mission of the European Space Agency (ESA) has been routinely observing Solar System objects (SSOs) since the beginning of its operations in August 2014. The Gaia data release three (DR3) includes, for the first time, the mean reflectance spectra of a selected sample of 60 518 SSOs, primarily asteroids, observed between August 5, 2014, and May 28, 2017. Each reflectance spectrum was derived from measurements obtained by means of the Blue and Red photometers (BP/RP), which were binned in 16 discrete wavelength bands. For every spectrum, the DR3 also contains additional information about the data quality for each band.Aims. We describe the processing of the Gaia spectral data of SSOs, explaining both the criteria used to select the subset of asteroid spectra published in Gaia DR3, and the different steps of our internal validation procedures. In order to further assess the quality of Gaia SSO reflectance spectra, we carried out external validation against SSO reflectance spectra obtained from ground-based and space-borne telescopes and available in the literature; we present our validation approach.Methods. For each selected SSO, an epoch reflectance was computed by dividing the calibrated spectrum observed by the BP/RP at each transit on the focal plane by the mean spectrum of a solar analogue. The latter was obtained by averaging the Gaia spectral measurements of a selected sample of stars known to have very similar spectra to that of the Sun. Finally, a mean of the epoch reflectance spectra was calculated in 16 spectral bands for each SSO.Results.Gaia SSO reflectance spectra are in general agreement with those obtained from a ground-based spectroscopic campaign specifically designed to cover the same spectral interval as Gaia and mimic the illumination and observing geometry characterising Gaia SSO observations. In addition, the agreement between Gaia mean reflectance spectra and those available in the literature is good for bright SSOs, regardless of their taxonomic spectral class. We identify an increase in the spectral slope of S-type SSOs with increasing phase angle. Moreover, we show that the spectral slope increases and the depth of the 1 μm absorption band decreases for increasing ages of S-type asteroid families. The latter can be interpreted as proof of progressive ageing of S-type asteroid surfaces due to their exposure to space weathering effects