Joshua D. Gottlieb: Research
Publications
The Wealth of Cities: Agglomeration Economies and Spatial Equilibrium in the United States, with Edward Glaeser.
Empirical research on cities starts with a spatial equilibrium condition: workers and firms are assumed to be indifferent across space. This condition implies that research on cities is different from research on countries, and that work on places within countries needs to consider population, income and housing prices simultaneously. Housing supply elasticity will determine whether urban success shows up in more people or higher incomes. Urban economists generally accept the existence of agglomeration economies, which exist when productivity rises with density, but estimating the magnitude of those economies is difficult. Some manufacturing firms cluster to reduce the costs of moving goods, but this force no longer appears to be important in driving urban success. Instead, modern cities are far more dependent on the role that density can play in speeding the flow of ideas. Finally, urban economics has some insights to offer related topics such as growth theory, national income accounts, public economics and housing prices.
Journal of Economic Literature, December 2009 | NBER, March 2009.
Hypoxia, Not the Frequency of Sleep Apnea, Induces
Acute Hemodynamic Stress
in Patients with Chronic Heart Failure, J.D. Gottlieb et al.
Joshua Gottlieb, Alan Schwartz, Joanne Marshall, Pamela Ouyang, Linda Kern, Veena Shetty, Maria Trois, Naresh Punjabi, Cynthia Brown, Samer Najjar and Stephen Gottlieb.
Objectives: This study was conducted to evaluate whether brain (B-type) natriuretic peptide (BNP) changes during sleep are associated with the frequency and severity of apneic/hypopneic episodes, intermittent arousals, and hypoxia.
Background: Sleep apnea is strongly associated with heart failure (HF) and could conceivably worsen HF through increased sympathetic activity, hemodynamic stress, hypoxemia, and oxidative stress. If apneic activity does cause acute stress in HF, it should increase BNP.
Methods: Sixty-four HF patients with New York Heart Association functional class II and III HF and ejection fraction <40% underwent a baseline sleep study. Five patients with no sleep apnea and 12 with severe sleep apnea underwent repeat sleep studies, during which blood was collected every 20 min for the measurement of BNP. Patients with severe sleep apnea also underwent a third sleep study with frequent BNP measurements while they were administered oxygen. This provided 643 observations with which to relate apnea to BNP. The association of log BNP with each of 6 markers of apnea severity was evaluated with repeated measures regression models.
Results: There was no relationship between BNP and the number of apneic/hypopneic episodes or the number of arousals. However, the burden of hypoxemia (the time spent with oxygen saturation <90%) significantly predicted BNP concentrations; each 10% increase in duration of hypoxemia increased BNP by 9.6% (95% confidence interval: 1.5% to 17.7%, p = 0.02).
Conclusions: Hypoxemia appears to be an important factor that underlies the impact of sleep abnormalities on hemodynamic stress in patients with HF. Prevention of hypoxia might be especially important for these patients.
Journal of the American College of Cardiology, October 27, 2009 | Journal of Cardiac Failure, August 2009 (Supplement).
Data and code available here.
The Economics of Place-Making Policies, with Edward Glaeser.
Should the national government undertake policies aimed at strengthening the economies of particular localities or regions? Agglomeration economies and human capital spillovers suggest that such policies could enhance welfare. However, the mere existence of agglomeration externalities does not indicate which places should be subsidized. Without a better understanding of nonlinearities in these externalities, any government spatial policy is as likely to reduce as to increase welfare. Transportation spending has historically done much to make or break particular places, but current transportation spending subsidizes low-income, low-density places where agglomeration effects are likely to be weakest. Most large-scale place-oriented policies have had little discernable impact. Some targeted policies such as Empowerment Zones seem to have an effect but are expensive relative to their achievements. The greatest promise for a national place-based policy lies in impeding the tendency of highly productive areas to restrict their own growth through restrictions on land use.
Brookings Papers on Economic Activity, Spring 2008 | NBER, October 2008 | HIER, November 2008.
Data and code available here.
Urban Resurgence and the Consumer City, with Edward Glaeser.
Cities make it easier for humans to interact, and one of the main advantages of dense, urban areas is that they facilitate social interactions. This paper provides evidence for the US suggesting that the resurgence of big cities in the 1990s is due, in part, to the increased demand for these interactions and due to the reduction in big city crime, which had made it difficult for urban residents to enjoy these social amenities. However, while density is correlated with consumer amenities, we show that it is not correlated with social capital and that there is no evidence that sprawl has hurt civic engagement.
Urban Studies, July 2006 | HIER, February 2006.
Working Papers
Paper links from: NBER, SSRN, IDEAS, EconPapers, BEPress.
© 2007 by the President and Fellows of Harvard College