1/ Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers: A Randomized Controlled Trial
2/ "During the study period (3 April to 2 June 2020), Danish authorities did not recommend masking. Use was uncommon (<5%) outside hospitals.
"Participants were randomly assigned to mask/control groups.
"Those in the mask group received 50 3-layer, disposable surgical masks."
3/ "Participants received follow-up surveys to collect information on antibody test results, adherence to recommendations on time spent outside the home, development of symptoms, COVID-19 diagnosis based on PCR testing done in public hospitals, and known COVID-19 exposures."
4/ "A recommendation to wear a surgical mask when outside the home among others did not reduce, at conventional levels of stat. significance, incident SARS-CoV-2 infection vs. no mask recommendation. We designed the study to detect a reduction in infection rate from 2% to 1%."
5/ "The findings, however, should not be used to conclude that a recommendation for everyone to wear masks in the community would not be effective in reducing SARS-CoV-2 infections, as the trial did not test the role of masks in source control of SARS-CoV-2 infection."
6/ "The face masks were high-quality surgical masks with a filtration rate of 98%.
"Face shields covering the eyes has been advocated to halt the conjunctival route of transmission, but we observed no stat. significant interaction between wearers & nonwearers of eyeglasses."
7/ "Practical challenges to implementation include potentially incorrect wearing, reduced adherence, reduced durability depending on type of mask & occupation, weather, physical & psychological discomfort, and changing to less cautious behavior due to a false sense of security."
8/ More:
Assessing mandatory stay‐at‐home and business closure effects on the spread of COVID‐19
1/ BST Holdings, LLC. v. OSHA (United States Court of Appeals, Fifth Circuit; Nov 12, 2021)
"This case concerns OSHA’s most recent ETS requiring employees of covered employers to undergo COVID-19 vaccination or take weekly COVID-19 tests & wear a mask."
2/ NOTE: The tone and degree of expressed certainty in this document runs counter to most of the academic papers I read (one reason I stay away from material sourced from politics and law).
As always, when policy makers are concerned, take everything with an extra grain of salt.
3/ "In its fifty-year history, OSHA has issued just ten emergency temporary standards (ETSs). Six were challenged in court; only one survived.
1/ Failures of Pandemic Central Planning (Magness)
"Public health is acutely susceptible to knowledge problems, which foster the conditions for a public choice trap that causes proposed policy measures to become ineffectual or even counterproductive."
2/ "The criticisms of Snow – that he bucked scientific consensus, that his water-borne transmission theory contradicted a self-evident effect of widely observed odors, that he threatened to undermine the Health Board’s solutions to cholera – parallels the 2020 pandemic response."
3/ "The governments of both the U.S. and U.K. effectively endorsed the catastrophic forecasts of the ICL model along with its prescriptive approach of forestalling massive casualties by enacting a series of lockdown-style NPIs intended to control the replication of the virus."
2/ "Instead of simply asking what mask & non-mask wearers think of each other, we look at how information about others’ mask-wearing behavior influences cooperation when real money is at stake.
"We recruited an even distribution of subjects from different political affiliations.
3/ "Our experiment consisted of two main stages of incentivized Prisoner’s Dilemma (PD) games with & without subjects knowing their partners’ mask usage.
"Each subject’s answer to a hypothetical scenario was used to classify her as a mask wearer (MW) or a non-mask wearer (NMW).
1/ Institutional Investors and Stock Return Anomalies (Edelen, Ince, Kadlec)
"At the one-year horizon, institutions have a strong tendency to buy overvalued stocks (anomalies' short legs) and which have particularly negative ex-post abnormal returns."
2/ SIH = sophisticated institutions hypothesis (agents trading in a way that exploits anomaly return predictability)
"We assign anomalies to seven broad categories, choosing the one from each category with the most reliable alpha (highest t-statistic) during our sample period."
3/ "Because our central hypothesis centers around how institutional investors modify their portfolios as stocks take on anomaly characteristics, we examine changes in holdings rather than levels. We focus on the number of institutions holding a stock rather than % shares held."
1/ Combining Value and Momentum (Fisher, Shah, Titman)
"Simultaneously incorporating both value and momentum reduces transaction costs and better utilizes the information from unfavorably-ranked value and momentum stocks in a long-only portfolio."
2/ Ranks are based on percentile of aggregate market cap that a stock is above for each factor.
Turnover = total amount bought or sold each month / portfolio size
Bid/ask spreads have fallen dramatically in the past few decades, so two estimates of transaction costs are used.
3/ "Even though the percentage of aggregate market cap is similar for the small value and momentum portfolios, the small value portfolio tends to hold close to twice as many securities as the small momentum portfolio due to holding stocks with small market capitalizations."
1/ Global Assessment of the Impact of Masking on COVID-19: A Country Level Comparative and Retrospective Analyses Using the Richards Model (Mamun, Vejerano)
"Laboratory and modeling studies did not translate to a measurable difference in the real world."
2/ "We are unaware of studies assessing masks’ effectiveness using real cases from multiple countries.
"The filtration efficiency of ordinary surgical (~12%) or cloth-based masks (~10%) is inferior to high-efficiency masks (≥95%). Aerosol leakage is also higher due to poor fit.
3/ "The Richards model can reasonably estimate the time when a phase shift occurs during an outbreak (turning point, ti), the infection rate (r), the exponential nature of the epidemic (α).
"It applies best for a curve consisting of a single high peak and a turning point."