Increases in the prison population are due to the continuing increases in new admissions to prison and the number of parole violators returning to prison. The population level of California prisons is affected by voter initiatives, court decisions, legislation, and administrative policy. The revised Spring 1989 projection is that the institutional population will rise at a higher rate than was projected in Fall 1988, and the June 1990 prediction is for an even greater increase. 18 tables, 4 figures.