3876
NASA engineer's 'helical engine' may violate the laws of physics | Hacker News
"A really excellent, conceptually clear exposition of relativity is given in chapters 11 and 12 of Morin's Mechanics. The modified version of F=ma is covered in section 12.5. "
HN-comments  physics  to:watch  to:read 
7 days ago
The Simple Economics of Optimal Persuasion | Journal of Political Economy: Vol 127, No 5
"We propose a price-theoretic approach to Bayesian persuasion by establishing an analogy between the sender’s problem and finding Walrasian equilibria of a persuasion economy. The sender, who acts as a consumer, purchases posterior beliefs at their prices using the prior distribution as her endowment. A single firm has the technology to garble the state. Welfare theorems provide a verification tool for optimality of a persuasion scheme and characterize the structure of prices that support the optimal solution. This approach yields a tractable solution method for persuasion problems in which the sender’s utility depends only on the expected state."

What does this do? Is it a reinterpretation?
price-theory  piotr.dworczak  JPE  giorgio.martini  bayesian-persuasion 
8 days ago
Trouble in the Tails? What We Know about Earnings Nonresponse 30 Years after Lillard, Smith, and Welch | Journal of Political Economy: Vol 127, No 5
"Earnings nonresponse in household surveys is widespread, yet there is limited knowledge of how nonresponse biases earnings measures. We examine the consequences of nonresponse on earnings gaps and inequality using Current Population Survey individual records linked to administrative earnings data. The common assumption that earnings are missing at random is rejected. Nonresponse across the earnings distribution is U-shaped, highest in the left and right tails. Inequality measures differ between household and administrative data due in part to nonresponse. Nonresponse biases earnings differentials by race, gender, and education, particularly in the tails. Flexible copula-based models can account for nonrandom nonresponse."
data  non-response  NA  JPE  surveys 
8 days ago
The Neolithic Agricultural Revolution and the Origins of Private Property | Journal of Political Economy: Vol 127, No 5
"Familiar explanations of why hunter-gatherers first took up farming—superior labor productivity, population pressure, or adverse climate—receive little support from recent evidence. Farming would be an unlikely choice without possession-based private property, which appears to have existed among rare groups of sedentary hunter-gatherers who became the first farmers. Our model shows that among them, farming could have benefited first adopters because private possession was more readily established and defended for cultivated crops and domesticated animals than for the diffuse wild resources on which hunter-gatherers relied, thus explaining how farming could have been introduced even without a productivity advantage."

It'll be light on data, presumably?
samuel.bowles  evolutionary-economics  JPE 
8 days ago
University Choice: The Role of Expected Earnings, Nonpecuniary Outcomes, and Financial Constraints | Journal of Political Economy: Vol 127, No 5
"We investigate the determinants of students’ university choice in Pakistan, with a focus on monetary returns, nonpecuniary factors enjoyed at school, and financial constraints. To mitigate the identification problem concerning the separation of preferences, expectations, and market constraints, we use rich data on subjective expectations, with direct measures of financial constraints, to estimate a life-cycle model of school choice jointly with school-specific expectations of dropping out. We find that labor market prospects play a small role. Instead, nonpecuniary outcomes, such as the school’s ideology, are the major determinants. Policy simulations suggest that relaxing financial constraints would have large welfare gains."
basit.zafar  adeline.delavande  expectations  structural-estimation  JPE 
8 days ago
Denial and Alarmism in Collective Action Problems by Manuel Foerster, Joel J. van der Weele :: SSRN
"We analyze communication about the social returns to investment in a public good. We model two agents who have private information about these returns as well as their own taste for cooperation, or social preferences. Before deciding to contribute or not, each agent submits an unverifiable report about the returns to the other agent. We show that even if the public good benefits both agents, there are incentives to misrepresent information. First, others’ willingness to cooperate generates an incentive for “alarmism”, the exaggeration of social returns in order to opportunistically induce more investment. Second, if people also want to be perceived as cooperators, a “justification motive” arises for low contributors. As a result, equilibrium communication features “denial” about the returns, depressing contributions. We illustrate the model in the context of institutional inertia and the climate change debate."
climate-change  economics  manuel.foerster  joel.vanderweele 
12 days ago
A Model of Competing Narratives by Kfir Eliaz, Rani Spiegler :: SSRN
"We formalize the argument that political disagreements can be traced to a "clash of narratives". Drawing on the "Bayesian Networks" literature, we model a narrative as a causal model that maps actions into consequences, weaving a selection of other random variables into the story. An equilibrium is defined as a probability distribution over narrative-policy pairs that maximizes a representative agent's anticipatory utility, capturing the idea that public opinion favors hopeful narratives. Our equilibrium analysis sheds light on the structure of prevailing narratives, the variables they involve, the policies they sustain and their contribution to political polarization."
narratives  rani.spiegler  kfir.eliaz  stories  to:read 
12 days ago
Motivated Errors by Christine Exley, Judd B. Kessler :: SSRN
"Behavioral biases that cause errors in decision making are often blamed on cognitive limitations. We show that biases can also arise, or be exacerbated, because agents are motivated to make errors. In three experiments involving nearly 3200 participants, agents motivated to be selfish make simple computational errors and respond to the salience of information known to them, and agents motivated to believe they are high ability update on entirely uninformative signals. When we remove self-serving motives, agents appear completely (or much more) rational. Biases due to motivated errors survive standard debiasing interventions including providing experience, ensuring attention, and simplifying decisions."
christine.exley  judd.kessler  motivated-beliefs  ** 
12 days ago
Folklore
" Folklore is the collection of traditional beliefs, customs, and stories of a community, passed through the generations by word of mouth. This vast expressive body, studied by the corresponding discipline of folklore, has evaded the attention of economists. In this study we do four things that reveal the tremendous potential of this corpus for understanding comparative development and culture. First, we introduce and describe a unique catalogue of folklore that codes the presence of thousands of motifs for roughly 1,000 pre-industrial societies. Second, we use a dictionary-based approach to elicit group-specific measures of various traits related to the natural environment, institutional framework, and mode of subsistence. We establish that these proxies are in accordance with the ethnographic record, and illustrate how to use a group’s oral tradition to quantify non-extant characteristics of preindustrial societies. Third, we use folklore to uncover the historical cultural values of a group. Doing so allows us to test various influential conjectures among social scientists including the original affluent society, the culture of honor among pastoralists, the role of family in extended kinship systems and the intensity of trade and rule-following norms in politically centralized group. Finally, we explore how cultural norms inferred via text analysis of oral traditions predict contemporary attitudes and beliefs."
self-beliefs  identity  folklore  narratives  economics  to:read  story-telling  social-norms 
12 days ago
Equity Concerns are Narrowly Framed
" We show that individuals narrowly bracket their equity concerns. Across four experiments including 1,600 subjects, individuals equalize components of payoffs rather than overall payoffs. When earnings are comprised of "small tokens" worth 1 cent and "large tokens" worth 2 cents, subjects frequently equalize the distribution of small (or large) tokens rather than equalizing total earnings. When payoffs are comprised of time and money, subjects similarly equalize the distribution of time (or money) rather than total payoffs. In addition, subjects are more likely to equalize time than money. These findings can help explain a variety of behavioral phenomena including the structure of social insurance programs, patterns of public good provision, and why transactions that turn money into time are often deemed repugnant. "
christine.exley  judd.kessler  narrow-bracketing  social-preferences 
12 days ago
American Economic Association
" In this paper, we provide a perspective into the main ideas and findings emerging from the growing literature on motivated beliefs and reasoning. This perspective emphasizes that beliefs often fulfill important psychological and functional needs of the individual. Economically relevant examples include confidence in ones' abilities, moral self-esteem, hope and anxiety reduction, social identity, political ideology, and religious faith. People thus hold certain beliefs in part because they attach value to them, as a result of some (usually implicit) tradeoff between accuracy and desirability. In a sense, we propose to treat beliefs as regular economic goods and assets--which people consume, invest in, reap returns from, and produce, using the informational inputs they receive or have access to. Such beliefs will be resistant to many forms of evidence, with individuals displaying non-Bayesian behaviors such as not wanting to know, wishful thinking, and reality denial."
roland.benabou  jean.tirole  motivated-beliefs  JEP  to:read 
12 days ago
Narratives, Imperatives, and Moral Reasoning
" By downplaying externalities, magnifying the cost of moral behavior, or suggesting not being pivotal, exculpatory narratives can allow individuals to maintain a positive image when in fact acting in a morally questionable way. Conversely, responsibilizing narratives can help sustain better social norms. We investigate when narratives emerge from a principal or the actor himself, how they are interpreted and transmitted by others, and when they spread virally. We then turn to how narratives compete with imperatives (general moral rules or precepts) as alternative modes of communication to persuade agents to behave in desirable ways. "
armin.falk  roland.benabou  jean.tirole  narratives  to:read  NBER 
12 days ago
Willpower and Personal Rules | Journal of Political Economy: Vol 112, No 4
"

We develop a theory of internal commitments or “personal rules” based on self‐reputation over one’s willpower, which transforms lapses into precedents that undermine future self‐restraint. The foundation for this mechanism is the imperfect recall of past motives and feelings, leading people to draw inferences from their past actions. The degree of self‐control an individual can achieve is shown to rise with his self‐confidence and decrease with prior external constraints. On the negative side, individuals may adopt excessively rigid rules that result in compulsive behaviors such as miserliness, workaholism, or anorexia. We also study the cognitive basis of self‐regulation, showing how it is constrained by the extent to which self‐monitoring is subject to opportunistic distortions of memory or attribution, and how rules for information processing can themselves be maintained."
roland.benabou  jean.tirole  JPE  willpower 
12 days ago
Beyond choice: investigating the sensitivity and validity of measures of strength of preference | SpringerLink
"Many experiments investigating different decision theories have relied heavily on pairwise choices between lotteries. These are easy to incentivise, but often yield only limited dichotomous information. This paper considers whether respondents’ judgments about their strength of preference (SoP) for one alternative over another can usefully supplement standard choice data. We report extensive evidence that such judgments show sensitivity to variations in question format and parameter values in the directions we should expect, not only within-subject but also between-sample. We illustrate how such judgments can usefully supplement standard pairwise choice data and enrich our understanding of observed behaviour."
choices  revealed-preference 
20 days ago
The Labor of Division: Returns to Compulsory High School Math Coursework | Journal of Labor Economics: Vol 37, No 4
"Despite great focus on and public investment in STEM education, little causal evidence connects quantitative coursework to students’ economic outcomes. I show that state changes in minimum high school math requirements substantially increase black students’ completed math coursework and their later earnings. The marginal student’s return to an additional math course is 10%, roughly half the return to a year of high school, and is partly explained by a shift toward more cognitively skilled occupations. White students’ coursework and earnings are unaffected. Rigorous standards for quantitative coursework can close meaningful portions of racial gaps in economic outcomes."
maths  US 
21 days ago
The Allocation of Talent and U.S. Economic Growth - Hsieh - 2019 - Econometrica - Wiley Online Library
"

In 1960, 94 percent of doctors and lawyers were white men. By 2010, the fraction was just 62 percent. Similar changes in other highly‐skilled occupations have occurred throughout the U.S. economy during the last 50 years. Given that the innate talent for these professions is unlikely to have changed differently across groups, the change in the occupational distribution since 1960 suggests that a substantial pool of innately talented women and black men in 1960 were not pursuing their comparative advantage. We examine the effect on aggregate productivity of the convergence in the occupational distribution between 1960 and 2010 through the prism of a Roy model. Across our various specifications, between 20% and 40% of growth in aggregate market output per person can be explained by the improved allocation of talent."

Nice.
talent  human-capital  ECMA  to:read-if-not-too-ECMA 
21 days ago
AEAweb Journal Articles Display
" Abstract: Mark Granovetter has written a deep and wide-ranging book on economy and society entitled Society and Economy: Frameworks and Principles. Economists, in particular, will find his discussion on the role of social networks in understanding the problem of aggregation—from micro foundations to large-scale institutional phenomena—especially relevant. And they will find much to ponder over the ways in which overlapping structures—of networks and institutions—shape human behavior and determine aggregate economic outcomes. The high-level and parsimonious style of this book is distinctive and sets it apart from much of contemporary social science. This style and the apparent unwillingness to engage closely with research developments over the past two decades may, however, mean that the book will have limited influence on ongoing and future research. "
granovetter  to:read  sanjeev.goyal  books  JEL 
21 days ago
AEAweb Journal Articles Display
" Abstract: In order to clarify the potential impact of a basic income, we argue that any discussion on whether to adopt a basic income policy should be framed within the greater context of the transfer system as a whole. In particular, such discussion should consider separately the issues of (i) the desired income distribution to be achieved and (ii) the most efficient way of achieving it through a transfer system. Further, we stress the importance of the non-take-up phenomenon in current transfer systems and discuss the potential necessity of a basic income policy in the age of automation. "
to:read  books  automation  basic-income 
21 days ago
AEAweb Journal Articles Display
" Abstract: An ever-increasing share of human interaction, communication, and culture is recorded as digital text. We provide an introduction to the use of text as an input to economic research. We discuss the features that make text different from other forms of data, offer a practical overview of relevant statistical methods, and survey a variety of applications. "
matt.taddy  matthew.gentzkow  JEL  ML  text-as-data  bryan.kelly  to:read? 
21 days ago
AEAweb Journal Articles Display
" Abstract: A statistician takes an action on behalf of an agent, based on the agent's self-reported personal data and a sample involving other people. The action that he takes is an estimated function of the agent's report. The estimation procedure involves model selection. We ask the following question: Is truth-telling optimal for the agent given the statistician's procedure? We analyze this question in the context of a simple example that highlights the role of model selection. We suggest that our simple exercise may have implications for the broader issue of human interaction with machine learning algorithms. "
rani.spiegler  kfir.eliaz  to:read  ML  aiconomics  AER:I 
21 days ago
What do Workplace Wellness Programs do? Evidence from the Illinois Workplace Wellness Study* | The Quarterly Journal of Economics | Oxford Academic
"Workplace wellness programs cover over 50 million U.S. workers and are intended to reduce medical spending, increase productivity, and improve well-being. Yet limited evidence exists to support these claims. We designed and implemented a comprehensive workplace wellness program for a large employer and randomly assigned program eligibility and financial incentives at the individual level for nearly 5,000 employees. We find strong patterns of selection: during the year prior to the intervention, program participants had lower medical expenditures and healthier behaviors than nonparticipants. The program persistently increased health screening rates, but we do not find significant causal effects of treatment on total medical expenditures, other health behaviors, employee productivity, or self-reported health status after more than two years. Our 95% confidence intervals rule out 84% of previous estimates on medical spending and absenteeism."
QJE  health  personnel-economics 
21 days ago
Industrial Policies in Production Networks* | The Quarterly Journal of Economics | Oxford Academic
"Many developing economies adopt industrial policies favoring selected sectors. Is there an economic logic to this type of intervention? I analyze industrial policy when economic sectors form a production network via input-output linkages. Market imperfections generate distortionary effects that compound through backward demand linkages, causing upstream sectors to become the sink for imperfections and have the greatest size distortions. My key finding is that the distortion in sectoral size is a sufficient statistic for the social value of promoting that sector; thus, there is an incentive for a well-meaning government to subsidize upstream sectors. Furthermore, sectoral interventions’ aggregate effects can be simply summarized, to first order, by the cross-sector covariance between my sufficient statistic and subsidy spending. My sufficient statistic predicts sectoral policies in South Korea in the 1970s and modern-day China, suggesting that sectoral interventions might have generated positive aggregate effects in these economies."
sufficient-statistics  networks  ernest.liu 
21 days ago
Uniform Pricing in U.S. Retail Chains* | The Quarterly Journal of Economics | Oxford Academic
"We show that most U.S. food, drugstore, and mass-merchandise chains charge nearly uniform prices across stores, despite wide variation in consumer demographics and competition. Demand estimates reveal substantial within-chain variation in price elasticities and suggest that the median chain sacrifices $16 million of annual profit relative to a benchmark of optimal prices. In contrast, differences in average prices between chains are broadly consistent with the optimal benchmark. We discuss a range of explanations for nearly uniform pricing, highlighting managerial inertia and brand image concerns as mechanisms frequently mentioned by industry participants. Relative to our optimal benchmark, uniform pricing may significantly increase the prices paid by poorer households relative to the rich, dampen the response of prices to local economic shocks, alter the analysis of mergers in antitrust, and shift the incidence of intranational trade costs."
pricing  stefano.dellavigna  matthew.gentzkow  QJE  to:read 
21 days ago
Promotions and the Peter Principle* | The Quarterly Journal of Economics | Oxford Academic
"The best worker is not always the best candidate for manager. In these cases, do firms promote the best potential manager or the best worker in their current job? Using microdata on the performance of sales workers at 131 firms, we find evidence consistent with the Peter Principle, which proposes that firms prioritize current job performance in promotion decisions at the expense of other observable characteristics that better predict managerial performance. We estimate that the costs of promoting workers with lower managerial potential are high, suggesting either that firms are making inefficient promotion decisions or that the benefits of promotion-based incentives are great enough to justify the costs of managerial mismatch. We find that firms manage the costs of the Peter Principle by placing less weight on sales performance in promotion decisions when managerial roles entail greater responsibility and when frontline workers are incentivized by strong pay for performance."

Neat.
personnel-economics  QJE  kelly.shue  danielle.li  alan.benson  firms  promotions 
21 days ago
AEAweb Journal Articles Display
" Abstract: Using Danish administrative data, we study the impacts of children on gender inequality in the labor market. The arrival of children creates a long-run gender gap in earnings of around 20 percent driven by hours worked, participation, and wage rates. We identify mechanisms driving these "child penalties" in terms of occupation, sector, and firm choices. We find that the fraction of gender inequality caused by child penalties has featured a dramatic increase over the last three to four decades. Finally, we show that child penalties are transmitted through generations, from parents to daughters, suggesting an influence of childhood environment on gender identity. "

I don't know what the 'penalties are transmitted ... from parents to daughters' means, should read that.
gender  education  henrik.kleeven  AEJ 
21 days ago
AEAweb Journal Articles Display
" Abstract: This paper develops a new approach to test for downward wage rigidity by examining transitory shocks to labor demand (i.e., rainfall) across 600 Indian districts. Nominal wages rise during positive shocks but do not fall during droughts. In addition, transitory positive shocks generate ratcheting: after they have dissipated, wages do not adjust back down. Ratcheting reduces employment by 9 percent, indicating that rigidities distort employment levels. Inflation, which is unaffected by local rainfall, enables downward real wage adjustments—offering causal evidence for its labor market effects. Surveys suggest that individuals believe nominal wage cuts are unfair and lead to effort reductions. "

This sounds like some really interesting stuff, even if the rainfall isn't fully exogenous (can't remember who showed that and how much of a problem that'd be here - Sarsons?).
supreet.kaur  ****  inflation  behavioral-economics  macroeconomics  to:read 
21 days ago
AEAweb Journal Articles Display
" Abstract: We examine ways to measure the amount of information generated by a piece of news and the amount of uncertainty implicit in a given belief. Say a measure of information is valid if it corresponds to the value of news in some decision problem. Say a measure of uncertainty is valid if it corresponds to expected utility loss from not knowing the state in some decision problem. We axiomatically characterize all valid measures of information and uncertainty. We show that if measures of information and uncertainty arise from the same decision problem, then they are coupled in that the expected reduction in uncertainty always equals the expected amount of information generated. We provide explicit formulas for the measure of information that is coupled with any given measure of uncertainty and vice versa. Finally, we show that valid measures of information are the only payment schemes that never provide incentives to delay information revelation. "
emir.kamenica  alex.frankel  information  to:read  ****  beliefs  AER 
21 days ago
AEAweb Journal Articles Display
" Abstract: We model the dynamics of discrimination and show how its evolution can identify the underlying source. We test these theoretical predictions in a field experiment on a large online platform where users post content that is evaluated by other users on the platform. We assign posts to accounts that exogenously vary by gender and evaluation histories. With no prior evaluations, women face significant discrimination. However, following a sequence of positive evaluations, the direction of discrimination reverses: women's posts are favored over men's. Interpreting these results through the lens of our model, this dynamic reversal implies discrimination driven by biased beliefs. "
aislinn.bohren  alex.imas  discrimination  AER 
21 days ago
AEAweb Journal Articles Display
" Abstract: We propose a new channel to account for the difficulties of individuals with contingent reasoning: the presence of uncertainty. When moving from an environment with one state of known value to one with multiple possible values, two changes occur. First, the number of values to consider increases. Second, the value of the state is uncertain. We show in an experiment that this lack of certainty, or the loss of the Power of Certainty, impedes payoff maximization and that it accounts for a substantial portion of the difficulties with contingent reasoning. "
contingent-reasoning  counterfactual-reasoning  biases  muriel.niederle  emmanuel.vespa  AER 
21 days ago
How Destructive Is Innovation? - Garcia‐Macia - 2019 - Econometrica - Wiley Online Library
"

Entrants and incumbents can create new products and displace the products of competitors. Incumbents can also improve their existing products. How much of aggregate productivity growth occurs through each of these channels? Using data from the U.S. Longitudinal Business Database on all nonfarm private businesses from 1983 to 2013, we arrive at three main conclusions: First, most growth appears to come from incumbents. We infer this from the modest employment share of entering firms (defined as those less than 5 years old). Second, most growth seems to occur through improvements of existing varieties rather than creation of brand new varieties. Third, own‐product improvements by incumbents appear to be more important than creative destruction. We infer this because the distribution of job creation and destruction has thinner tails than implied by a model with a dominant role for creative destruction.
"
innovation  economics  ECMA  2019 
21 days ago
Practical Microservices: Build Event-Driven Architectures with Event Sourcing and CQRS by Ethan Garofolo | The Pragmatic Bookshelf
"

MVC and CRUD make software easier to write, but harder to change. Microservice-based architectures can help even the smallest of projects remain agile in the long term, but most tutorials meander in theory or completely miss the point of what it means to be microservice-based. Roll up your sleeves with real projects and learn the most important concepts of evented architectures. You’ll have your own deployable, testable project and a direction for where to go next.
"
books  pragprog  web-development 
27 days ago
Arbitrage Or Narrow Bracketing? On Using Money to Measure Intertemporal Preferences
" If experimental subjects arbitrage against market interest rates when making intertemporal allocations of cash, the data will reveal nothing about subjects' discount rates, only uncovering subjects' market interest rates. If they frame choices narrowly, market rates will not be salient and the experiment will uncover subjects' utility discount rates. We test arbitrage directly by forcing all transactions with subjects to be instant electronic bank transfers, thus making arbitrage easy and salient. We also employ four decision frames to test alternative hypotheses. Our evidence contradicts arbitrage, supports money as a valid reward, and suggests framing as a correlate with present bias. "
james.andreoni  present-bias  money-is-not-consumption  michael.kuhn 
5 weeks ago
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