A gate rule is a business rule that allows you to sample a lot and determine if further inspection/processing is required. Typically it is expressed as a sample size /percentage followed by a number of allowed errors. Should the number of errors exceed the allowed amount, then the lot can be placed on hold and/or rerouted to a step that performs a full inspection of the lot. The gate rule states the sample size (either in units or in percentage of total lot size), the number of allowed failures (again in units or percentage), and the action to take (place lot on hold, set a failure flag, or both). The failure flag is used to redirect the lot to the 100% inspection step. In the InSite system, the gate rule is defined and attached to a spec or a Bill of Process. When a step with an attached gate rule is reached, partial processing is allowed and the operator can display the gate rule to see what sample size to use.