TY - JOUR AU - Glaeser,Edward L. AU - Kerr,William R. AU - Ponzetto,Giacomo A.M. TI - Clusters of Entrepreneurship JF - National Bureau of Economic Research Working Paper Series VL - No. 15377 PY - 2009 Y2 - September 2009 UR - http://www.nber.org/papers/w15377 L1 - http://www.nber.org/papers/w15377.pdf N1 - Author contact info: Edward L. Glaeser Department of Economics 315A Littauer Center Harvard University Cambridge, MA 02138 Tel: 617/495-0575 Fax: 617/495-7730 E-Mail: eglaeser@harvard.edu William R. Kerr Harvard Business School Rock Center 212 Soldiers Field Boston, MA 02163 Tel: 617/496-7021 E-Mail: wkerr@hbs.edu Giacomo Ponzetto CREI - Universitat Pompeu Fabra C/ Ramon Trias Fargas, 25-27 08005 Barcelona Spain Tel: +34 93 542 2829 Fax: +34 93 542 2826 E-Mail: gponzetto@crei.cat M1 - published as Edward L. Glaeser, William R. Kerr, Giacomo A. M. Ponzetto. "Clusters of Entrepreneurship," in Edward Glaeser, Stuart Rosenthal and William Strange, organizers, "Cities and Entrepreneurship" Journal of Urban Economics, Vol. 67, no. 1 (2010) AB - Employment growth is strongly predicted by smaller average establishment size, both across cities and across industries within cities, but there is little consensus on why this relationship exists. Traditional economic explanations emphasize factors that reduce entry costs or raise entrepreneurial returns, thereby increasing net returns and attracting entrepreneurs. A second class of theories hypothesizes that some places are endowed with a greater supply of entrepreneurship. Evidence on sales per worker does not support the higher returns for entrepreneurship rationale. Our evidence suggests that entrepreneurship is higher when fixed costs are lower and when there are more entrepreneurial people. ER -