This document contains testimonies and prepared statements from the Congressional hearing called to examine the difficulties associated with the lack of reliable demographic data for use in planning appropriate assistance to "special populations" of older Americans, including minorities, persons with disabilities, the rural elderly, older women, frail persons, and low-income persons. In his opening statement, Representative Edward Roybal stresses the importance of the hearing given current propsals for changes in the 1990 Census. An opening statement by Representative James Jeffords and prepared statements by Representatives Mervyn Dymally, Matthew Rinaldo, and Constance Morella are included. John G. Keane, director of the Bureau of the Census, United States Department of Commerce discusses interagency cooperative efforts, Census Bureau research and analysis on aging, the decennial Census and current surveys, and decennial Census questionnaire content and tabulations. Also providing testimony are: (1) Emily M. Agree, research associate from the Center for Population Research, Kennedy Institute of Ethics, Georgetown University; (2) Emily Gantz McKay, executive vice president of the National Council of La Raza; and (3) William M. Ortiz, executive director of the San Juan Center, Inc., Hartford, Connecticut. Testimonies focus on the problems of the Hispanic elderly and on the difficulties involved in obtaining reliable statistics. (NB)