Abstract

We study here what can be learned from our experience with COVID-19 vaccination for an initially naïve population, that can inform planning for vaccination against the next novel, highly transmissible pathogen. We focus on the first two pandemic years (wild strain through Delta), because after the Omicron wave in early 2022, few people were still SARS-CoV-2-naïve. Almost all were vaccinated, infected, or often both. We review the evidence on COVID-19 vaccine effectiveness (VE), waning effectiveness over time, and what we should expect about VE and waning from a future pathogen. As a basis for our analysis, we conducted a PRISMA-compliant review of all studies on PubMed through August 15, 2022 reporting VE against four endpoints: any infection, symptomatic infection, hospitalization, and death, for the four principal vaccines used in developed Western countries (BNT162b2, mRNA1273, Ad26.CoV2.S, and ChAdOx1-S). The mRNA vaccines (BNT162b2, mRNA1273) had high initial VE against all endpoints but protection waned after approximately six months, with BNT162b2 declining faster than mRNA1273. Both mRNA vaccines initially outperformed the viral vector vaccines. A third “booster” dose, roughly six months after the primary doses, substantially reduced symptomatic infection, severe disease, and mortality, and in hindsight should be seen as part of the normal vaccination schedule

Abstract

This paper estimates the effect of Disability Insurance and Supplemental Security Income receipt on mortality for individuals on the margin of being allowed versus denied benefits. Exploiting the random assignment of administrative law judges to disability insurance cases, we find that benefit allowance increases 10-year mortality rates by 2.8 percentage points for marginal beneficiaries. However, using a Marginal Treatment Effects approach, we find evidence that benefit receipt reduces mortality for inframarginal beneficiaries, who are typically less healthy than marginal beneficiaries. Furthermore, we find suggestive evidence that allowance reduces mortality among those with expensive health conditions such as cancer.

Read at SSRN.

Abstract

We take advantage of the Brazilian mandatory corporate governance (CG) reporting system to build an overall Brazil Corporate Governance Index (BCGI) and subindices (CGIs), and track changes in firms’ scores over the 10-year period from 2010-2019. We show that overall CG level improved significantly between 2010 and 2019, with most of the improvement over the first part of this period. The improvement has two sources: an increase in the proportion of high-standard listings (Novo Mercado and Level 2, NML2) versus low-standard listings (Level 1 and regular, L1R), and within-firm improvement in CG practices. In the first half of the sample period, both NML2 and L1R firms improved CG practices considerably. Overall improvement in the second half of the sample period reflects an increasing proportion of NML2 firms, plus gradual improvement in L1R CG levels; with nearly constant NML2 levels. Improvements were stronger for Board Procedure and Disclosure. Firms in both listings improved their CG. Overall improvement was stronger in NML2 than in L2R, but was concentrated in the period from 2010-2015.

Abstract

We study the evolution of corporate governance (CG) practices in Brazil over 2010-2019, using a country-specific Brazil Corporate Governance Index (BCGI) validated in prior work. We study separately firms in high-governance and low-governance legal regimes, in a single country. CG improved considerably in Brazil over 2010-2015, with much smaller changes over 2015-2019. Positive CG changes are much more common than negative changes. Some firms made only minimal changes, despite low initial CG levels. We also study which firm financial factors predict both CG levels and changes in levels. None of the firm financial variables we study consistently predicts CG levels. However, for CG changes, a measure of equity financing need predicts CG improvements in the first half of the sample period, but only for firms in the lower governance regime, not for firms in the higher regime. This is the first article to find evidence for firm financial characteristics predicting CG changes, consistent with theoretical predictions, including stronger effects for firms in the lower governance regime.

Importance  Many physicians believe that most medical malpractice claims are random events. This study assessed the association of prior paid claims (including a single prior claim) with future paid claims; whether public disclosure of prior paid claims affects future paid claims; and whether the association of prior and future paid claims decayed over time.

Objective  To examine the association of 1 or more prior paid medical malpractice claims with future paid claims.

Design, Setting, and Participants  This study assessed the association between prior paid claims (including a single prior claim) with future claims; whether public disclosure of prior claims affects future paid claims; and whether the association of prior and future paid claims decayed over time. This retrospective case-control study included all 881,876 licensed physicians in the US. All data analysis took place between July, 2018 and January, 2023.

Exposure  Paid medical malpractice claims.

Main Outcome and Measures  Association between a prior paid medical malpractice claim and likelihood of a paid claim in a future period, compared with simulated results expected if paid claims are random events. Using the same outcomes, we also assessed whether public disclosure of paid claims affects future paid claim rates.

Results  This study included all 881,876 physicians licensed to practice in the US at the time of the study. Overall, 3.3% of the 841,?961 physicians with 0 paid claims in the prior period had 1 or more claims in the future period vs 12.4% of the 34?,512 physicians with 1 paid claim in the prior period; 22.4% of the 4,189 physicians with 2 paid claims in the prior period; and 37% of the 1,214 physicians with 3 paid claims in the prior period. The association between prior claims and future claims was similar for high-medical-malpractice-risk and lower-risk specialties; 1 prior-period claim was associated with a 3.1 times higher likelihood of a future-period claim for high-risk specialties (95% CI, 2.8-3.4) vs a 4.2 times higher likelihood for lower-risk specialties (95% CI, 3.8-4.6). The predictive power of a prior paid claim for future claims declined gradually as the time since the prior claim increased, for prior or future periods up to 10 years. Public disclosure did not affect the association between prior and future paid claims.

Conclusions and Relevance  In this study of paid medical malpractice claims for all US physicians, a single prior paid claim was associated with substantial, long-lived higher future claim risk, independent of whether a physician was practicing in a high- or low-risk specialty, or whether a state publicly disclosed paid claims. Timely, noncoercive intervention, including education, has the potential to reduce future claims.

Abstract

Background. The need for COVID-19 vaccine booster shots is controversial. When boosters were under active review in the U.S. in 2021, Krause et al.[1] and others have argued that need for a COVID-19 booster for all adults has not been sufficiently established. In late 2021, U.S. regulators initially limited booster eligibility, waited months before allowing boosters for all adults, and even longer before recommending them, with public health officials sending mixed messages on booster value. We conduct a systematic review of COVID-19 vaccine effectiveness (VE) for primary and booster doses.

Methods. We conducted a systematic review of studies reporting COVID-19 vaccine efficacy or VE against four endpoints: any infection, symptomatic infection, hospitalization, and death for the four principal vaccines used in developed Western countries (BNT162b2, mRNA1273, Ad26.CoV2.S, and ChAdOx1-S), waning VE, and booster VE, during the period of Delta-variant prevalence. We reviewed all studies appearing on PubMed over Jan. 1, 2021 through March 31, 2022, supplemented with our own knowledge of other sources. 63 studies met defined inclusion and exclusion criteria.

Findings. The mRNA vaccines (BNT162b2, mRNA1273) had very high initial VE but experienced significant VE waning after approximately six months, including against severe disease and mortality, with BNT162b2 declining faster than mRNA1273. Both mRNA vaccines outperformed the Ad26.CoV2.S and ChAdOx1-S viral vector vaccines. Booster doses reduced symptomatic infection, severe disease, and mortality. Initial evidence supports booster value against the Omicron variant.

Interpretation. Strong epidemiological evidence supports waning VE for primary COVID-19 vaccination and the value of a booster dose, roughly 6 months after initial vaccination. The emergence of the Omicron variant strengthens the value of booster doses to recipients. Boosters also provide spillover benefits to others, both vaccinated and unvaccinated, by reducing downstream infections; reducing shortage risk for scarce COVID treatments; and reducing hospital overload.

Abstract

We study the factors that predict medical malpractice (“med mal”) insurance premia, using national data from Medical Liability Monitor over 1990 to 2017. A number of core findings are not easily explained by standard economic theory. First, we estimate long run elasticities of premia to insurers’ direct cost (payouts plus defense costs), allowing for lags of up to four years, of only around +0.40, when one might expect elasticities near one. Second, state caps on malpractice damages predict a roughly 50% higher ratio of premia to direct costs even though, in competitive markets, a damages cap should affect premia primarily through effect on cost. A difference-in-differences analysis of the “new cap” states that adopted caps during the early 2000’s provides evidence supporting a causal link between cap adoption and the ratio of premium to direct cost. Third, the premium-to-cost ratio, which one might expect to be fairly constant over time, instead varies widely both across states at a given time and within states across time. Our results suggest that insurance companies do not fully adjust revenues to changes in direct costs even over long time periods. Insurers in new-cap states have been able to charge apparently supra-competitive prices for a sustained period.

Abstract

Using hazard analysis, we study whether various physician characteristics, including prior paid claim history, gender, specialty, years of experience, type of degree (M.D. versus D.O.), country of medical school attendance (U.S. versus non-U.S.), and gender) predict future paid medical malpractice (“med mal”) claims, using detailed data on all licensed physicians and all paid claims in Illinois over a 25-year period. This level of granularity is not available using national data. After controlling for other factors, physicians with a single prior paid claim have a four-fold higher risk of future claims than physicians with zero prior paid claims. Male gender, attending a non-U.S. medical school, and practicing in a high-malpractice-risk specialty all predict higher paid claim risk. Paid claim risk is also higher for physicians with 6-15 prior years of experience than for those who are either earlier or later in their careers. We find having an M.D. (rather than a D.O.) is associated with higher paid claim risk, but only in our multiple-failure models.

Abstract

Corporate law generally makes voting power proportional to economic ownership. This serves several goals. Economic ownership gives shareholders an incentive to exercise voting power well. The coupling of votes and shares makes possible the market for corporate control. The power of economic owners to elect directors is also a core basis for the legitimacy of managerial authority. Both theory and evidence generally support the importance of linking votes to economic interest. Yet the derivatives revolution and other capital markets developments now allow both outside investors and insiders to readily decouple economic ownership of shares from voting rights. This decoupling, which we call the new vote buying, has emerged as a worldwide issue in the past several years. It is largely hidden from public view and mostly untouched by current regulation.

Hedge funds have been especially creative in decoupling voting rights from economic ownership. Sometimes they hold more votes than economic ownership – a pattern we call empty voting. In an extreme situation, a vote holder can have a negative economic interest and, thus, an incentive to vote in ways that reduce the company’s share price. Sometimes investors hold more economic ownership than votes, though often with morphable voting rights – the de facto ability to acquire the votes if needed. We call this situation hidden (morphable) ownership because the economic ownership and (de facto) voting ownership are often not disclosed.

This Article analyzes the new vote buying and its potential benefits and costs. We set out the functional elements of the new vote buying and develop a taxonomy of decoupling strategies. We also propose a near-term disclosure-based response and outline a menu of longer-term regulatory choices. Our disclosure proposal would simplify and partially integrate five existing, inconsistent ownership disclosure regimes, and is worth considering independent of its value with respect to decoupling. In the longer term, other responses may be needed: we discuss strategies focused on voting rights, voting architecture, and supply and demand forces in the markets on which the new vote buying relies.