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The Latest NBER Working Papers
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20 сентября, 22:25

Primary Care Physician Practice Styles and Patient Care: Evidence from Physician Exits in Medicare -- by Itzik Fadlon, Jessica N. Van Parys

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Primary care physicians (PCPs) provide frontline health care to patients in the U.S.; however, it is unclear how their practice styles affect patient care. In this paper, we estimate the long-lasting effects of PCP practice styles on patient health care utilization by focusing on Medicare patients affected by PCP relocations or retirements, which we refer to as "exits." Observing where patients receive care after these exits, we estimate event studies to compare patients who switch to PCPs with different practice style intensities. We find that PCPs have large effects on a range of aggregate utilization measures, including physician and outpatient spending and the number of diagnosed conditions. Moreover, we find that PCPs have large effects on the quality of care that patients receive, and that all of these effects persist for several years. Our results suggest that switching to higher-quality PCPs could significantly affect patients' longer-run health outcomes.

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20 сентября, 22:25

The Effect of High-Tech Clusters on the Productivity of Top Inventors -- by Enrico Moretti

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The high-tech sector is increasingly concentrated in a small number of expensive cities, with the top ten cities in “Computer Science”, “Semiconductors” and “Biology and Chemistry”, accounting for 70%, 79% and 59% of inventors, respectively. Why do inventors tend to locate near other inventors in the same field, despite the higher costs? I use longitudinal data on top inventors based on the universe of US patents 1971 - 2007 to quantify the productivity advantages of Silicon-Valley style clusters and their implications for the overall production of patents in the US. I relate the number of patents produced by an inventor in a year to the size of the local cluster, defined as a city × research field × year. I first study the experience of Rochester NY, whose high-tech cluster declined due to the demise of its main employer, Kodak. Due to the growth of digital photography, Kodak employment collapsed after 1996, resulting in a 49.2% decline in the size of the Rochester high-tech cluster. I test whether the change in cluster size affected the productivity of inventors outside Kodak and the photography sector. I find that between 1996 and 2007 the productivity of non-Kodak inventors in Rochester declined by 20.6% relative to inventors in other cities, conditional on inventor fixed effects. In the second part of the paper, I turn to estimates based on all the data in the sample. I find that when an inventor moves to a larger cluster she experiences significant increases in the number of patents produced and the number of citations received. Conditional on inventor, firm, and city × year effects, the elasticity of number of patents produced with respect to cluster size is 0.0662 (0.0138). The productivity increase follows the move and there is no evidence of pre-trends. IV estimates based on the geographical structure of firms with laboratories in multiple cities are statistically similar to OLS estimates. In the final part of the paper, I use the estimated elasticity of productivity with respect to cluster size to quantify the aggregate effects of geographical agglomeration on the overall production of patents in the US. I find macroeconomic benefits of clustering for the US as a whole. In a counterfactual scenario where the quality of U.S. inventors is held constant but their geographical location is changed so that all cities have the same number of inventors in each field, inventor productivity would increase in small clusters and decline in large clusters. On net, the overall number of patents produced in the US in a year would be 11.07% smaller.

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20 сентября, 22:25

Integration Costs and Missing Women in Firms -- by Conrad Miller, Jennifer Peck, Mehmet Seflek

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Where social norms favor gender segregation, firms may find it costly to employ both men and women. If the costs of integration are largely fixed, firms will integrate only if their expected number of female employees under integration exceeds some threshold. Motivated by a simple model of firm hiring, we develop a methodology that uses the distribution of female employment across firms to estimate the share of firms with binding integration costs and counterfactual female employment at all-male firms. We validate our approach using administrative data and unique policy variation from Saudi Arabia. We provide suggestive evidence that integration costs reduce aggregate female employment. Using survey data on manufacturing firms in 65 countries, we find significant integration costs in the Middle East, North Africa, and South Asia but not in other regions.

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20 сентября, 22:25

Work after Retirement: Worklife Transitions of Career Public Employess -- by Robert L. Clark, Robert G. Hammond, Siyan Liu

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Engaging in paid employment after claiming retirement benefits may be an important avenue for individuals to work longer as life expectancies rise. After separating from one’s career employer, individuals may engage in paid work to stay active or to supplement their current level of retirement savings or both. Individuals who choose not to work after claiming may be expressing their preference to stay retired, perhaps because their retirement income is sufficient. However, the decision to work after claiming may be driven by the lack of retirement planning and insufficient savings, while the lack of post-claiming work may reflect the inability to find adequate employment opportunities. We use administrative records merged with panel data from several surveys of public employees in North Carolina to study the decision to engage in paid work after claiming retirement benefits. More than 60 percent of active workers plan to work after claiming benefits, while only around 42 percent of the same sample of individuals have engaged in post-claiming paid work in the first few years after leaving public sector employment. Despite this gap, stated work plans are strongly predictive of actual post-claiming work behavior

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20 сентября, 22:25

Experimental Innovation Policy -- by Albert Bravo-Biosca

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Experimental approaches are increasingly being adopted across many policy fields, but innovation policy has been lagging. This paper reviews the case for policy experimentation in this field, describes the different types of experiments that can be undertaken, discusses some of the unique challenges to the use of experimental approaches in innovation policy, and summarizes some of the emerging lessons, with a focus on randomized trials. The paper concludes describing how at the Innovation Growth Lab we have been working with governments across the OECD to help them overcome the barriers to policy experimentation in order to make their policies more impactful.

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20 сентября, 22:25

Getting Tired of Your Friends: The Dynamics of Venture Capital Relationships -- by Qianqian Du, Thomas F. Hellmann

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Does doing more deals together always strengthen investor relationships? Based on the relationships of the top 50 US venture capital firms, this paper focuses on the strengths of relationships and their dynamic evolution. Empirical estimates indicate that having a deeper relationship leads to fewer, not more future coinvestments. Moreover, deeper relationships lead to lower exit performance, even after controlling for endogeneity. Interestingly, deeper relationships first lead to lower performance, and subsequently lead to a slowdown in the relationship intensity. Relationship effects are more negative for VC firms with less central network positions, and for deals made in “hot” investment markets.

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20 сентября, 22:25

Be Careful What You Ask For: Fundraising Strategies in Equity Crowdfunding -- by Thomas Hellmann, Ilona Mostipan, Nir Vulkan

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We use equity crowdfunding data to ask how fundraising amounts can be explained by what entrepreneurs ask for, versus what investors want to invest. The analysis exploits unique features of crowdfunding where entrepreneurs not only set investment goals, but also chose when to close their campaigns. More experienced and more educated founder teams ask for more. Their campaigns succeed more often, and they raise more money. Female teams ask for less, are equally successful, yet raise significantly less. They also wait longer before closing campaigns, suggesting they want to raise more than what they originally asked for.

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20 сентября, 22:25

Understanding Different Approaches to Benefit-Based Taxation -- by Robert Scherf, Matthew Weinzierl

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The normative principle of benefit-based taxation has exerted substantial influence on many areas of public finance, but it has been largely set aside in the modern theoretical approach to optimal income taxation, where welfarist objectives dominate. A prerequisite for that gap to close is the clarification of what benefit-based income taxation would mean, specifically in a first-best setting. This paper seeks to provide clear, accessible descriptions and novel graphical representations of four major approaches to first-best benefit-based taxation, explain how these approaches relate to each other, and apply them within the Classical Benefit-Based framework for optimal income taxation of Smith (1776).

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20 сентября, 22:25

Liquidity Deflation and Liquidity Trap under Flexible Prices: Some Microfoundations and Implications -- by Guillermo A. Calvo

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The paper discusses simple microfoundations for Liquidity Deflation (Calvo 2016, Chapter 2), which gives rise to liquidity trap under perfectly flexible prices/wages. Unlike Keynes (1936), this is a Supply Side Liquidity Trap, SSLT, not resolved by a fall in prices /wages, or massive helicopter increase in liquid government liabilities. However, escaping SSLT could be achieved by low policy interest rates on money (unless ZLB holds) and, more interestingly, higher inflation driven by administered prices/wages. Moreover, contrary to (Friedman 1969), under Liquidity Deflation the Optimal Quantity of Money does not call for liquidity satiation, and may be dangerously close to SSLT.

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20 сентября, 22:25

Experimentation and Startup Performance: Evidence from A/B testing -- by Rembrand Koning, Sharique Hasan, Aaron Chatterji

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Recent work argues that experimentation is the appropriate framework for entrepreneurial strategy. We investigate this proposition by exploiting the time-varying adoption of A/B testing technology, which has drastically reduced the cost of experimentally testing business ideas. This paper provides the first evidence of how digital experimentation affects the performance of a large sample of high-technology startups using data that tracks their growth, technology use, and product launches. We find that, despite its prominence in the business press, relatively few firms have adopted A/B testing. However, among those that do, we find increased performance on several critical dimensions, including page views and new product features. Furthermore, A/B testing is positively related to tail outcomes, with younger ventures failing faster and older firms being more likely to scale. Firms with experienced managers also derive more benefits from A/B testing. Our results inform the emerging literature on entrepreneurial strategy and how digitization and data-driven decision-making are shaping strategy.

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20 сентября, 22:25

Hitting the Elusive Inflation Target -- by Francesco Bianchi, Leonardo Melosi, Matthias Rottner

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Since the 2001 recession, average core inflation has been below the Federal Reserve’s 2% target. This deflationary bias is a predictable consequence of a low nominal interest rates environment in which the central bank follows a symmetric strategy to stabilize inflation. The deflationary bias increases if macroeconomic uncertainty rises or the natural real interest rate falls. An asymmetric rule according to which the central bank responds less aggressively to above-target inflation corrects the bias and allows inflation to converge to the central bank’s target. We show that adopting this asymmetric rule improves welfare and reduces the risk of self-fulfilling deflationary spirals. This approach does not entail any history dependence in setting the policy rate or any commitment to overshoot inflation after periods in which the lower bound constraint was binding.

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20 сентября, 22:25

Effect of Inquiry and Problem Based Pedagogy on Learning: Evidence from 10 Field Experiments in Four Countries -- by Rosangela Bando, Emma Näslund-Hadley, Paul Gertler

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This paper uses data from 10 at-scale field experiments in four countries to estimate the effect of inquiry- and problem-based pedagogy (IPP) on students’ mathematics and science test scores. IPP creates active problem-solving opportunities in settings that provide meaning to the child. Students learn by collaboratively solving real-life problems, developing explanations, and communicating ideas. Using individual-level data on 17,006 students, the analysis finds that after seven months IPP increased mathematics and science scores by 0.18 and 0.14 standard deviations, respectively, and by 0.39 and 0.23 standard deviations, respectively, after four years. We also identify important gender learning gaps with boys benefiting substantially more than girls. Our approach not only provides strong causal evidence, but also high external validity. These 10 experiments in four countries allow us to examine the effects of IPP across a wide set of geographic, socioeconomic, teacher background, and age/grade contexts (i.e., preschool and third and fourth grades). The results prove to be robust across these different contexts. The 10 RCTs were registered in the American Economic Association Registry for randomized control trials. See the supplementary materials for trial numbers.