The rate type determines the price per unit used to calculate costs for the assignment. In today's global economy, different resources and roles command varying levels of pay. Moreover, those rates can change over time. The price per unit, or rate, applied to a resource or role assignment for an activity is determined by that assignment's specific Rate Type or Rate Source field values.
A rate type is a user-defined title for a specific price-per-unit of work. Up to five global user-defined rate types can be defined as part of your enterprise data settings. Examples of rate types include Standard, Internal, External, Hourly, Weekly, and Special. To illustrate how they are used, a resource might be assigned at an Hourly rate of $175 per hour but for other assignments the same resource might be assigned at a Weekly rate of $5,000 per week or $125 per hour.