This study, based on the 1994 International Adult Literacy Survey and the 2003 Adult Literacy and Life Skills Survey, examines how literacy skills evolved during the nine-year span between the surveys. It showed that literacy skills are not a "static commodity acquired in youth and maintained throughout life". The study estimates that most Canadian adults experience, on average, a skill loss over their lifetime of about one grade level. The probability of whether a group will gain or lose literacy skills appears to depend on a variety of factors over which individuals and governments can exert some control. Available online in pdf or html formats.