Paul D. Allison Statistical Horizons, LLC Paul D. Allison, Ph.D., is Professor of Sociology at the University of Pennsylvania and President of Statistical Horizons. He is the author of numerous books and articles on statistical methods. He offers short courses on Survival Analysis, Categorical Data Analysis, Longitudinal Data Analysis and Missing Data. These courses are frequently presented as public seminars, and can also be given on-site at your firm. Prof. Allison is also available for statistical consulting on a variety of topics. To join our e-mail list, please click here. Schedule of Upcoming Seminars: Missing Data March 8-9, Lyon, France  April 23-24, Philadelphia Longitudinal Data Analysis May 7-8 Washington, DC (Using Stata) May 21-22 Los Angeles (Using SAS) Categorical Data Analysis July 12-16, Philadelphia Event History & Survival Analysis July 19-23, Philadelphia