The Stata Journal Volume 16 Number 4 2016 ® ® A Stata Press publication StataCorp LP College Station, Texas The Stata Journal Editors H. Joseph Newton Nicholas J. Cox Department of Statistics Department of Geography Texas A&M University Durham University College Station, Texas Durham, UK
[email protected] [email protected] Associate Editors Christopher F. Baum, Boston College Frauke Kreuter, Univ. of Maryland–College Park Nathaniel Beck, New York University Peter A. Lachenbruch, Oregon State University Rino Bellocco, Karolinska Institutet, Sweden, and Jens Lauritsen, Odense University Hospital University of Milano-Bicocca, Italy Stanley Lemeshow, Ohio State University Maarten L. Buis, University of Konstanz, Germany J. Scott Long, Indiana University A. Colin Cameron, University of California–Davis Roger Newson, Imperial College, London Mario A. Cleves, University of Arkansas for Austin Nichols, Urban Institute, Washington DC Medical Sciences Marcello Pagano, Harvard School of Public Health William D. Dupont , Vanderbilt University Sophia Rabe-Hesketh, Univ. of California–Berkeley Philip Ender , University of California–Los Angeles J. Patrick Royston, MRC Clinical Trials Unit, David Epstein, Columbia University London Allan Gregory, Queen’s University Mark E. Schaffer, Heriot-Watt Univ., Edinburgh James Hardin, University of South Carolina Jeroen Weesie, Utrecht University Ben Jann, University of Bern, Switzerland Ian White, MRC Biostatistics Unit, Cambridge Stephen Jenkins, London School of Economics and Nicholas J. G. Winter,UniversityofVirginia Political Science Jeffrey Wooldridge, Michigan State University Ulrich Kohler, University of Potsdam, Germany Stata Press Editorial Manager Stata Press Copy Editors Lisa Gilmore Adam Crawley, David Culwell,andDeirdre Skaggs The Stata Journal publishes reviewed papers together with shorter notes or comments, regular columns, book reviews, and other material of interest to Stata users.