Absolute" sodal mobility refers to the total amount of movement of people (e.g. an increase/decrease in household income irrespective of a change in the distribution of income), while "relative" sodal mobility refers to the upward or downward movement of a member of one sodal class compared with a member of another dass. The section begins with an analysis of income mobility in Viet Nam from 2002 to 2008. The concept of income mobility is significant for countries such as Viet Nam that have experienced stable, persistent economic growth and profound structural transformations.