The understanding of a filter's performance is often not only confusing but misleading. Automotive filters, for this discussion referring to engine lubrication filters, transmission fluid filters, and fuel filters, are no exception. Advanced filtration assessment techniques have been finding increasing use and application in many filter specifications for OEM and aftermarket use.This paper addresses the application of laboratory filter assessment methods to filter specification requirements. The component or system designer and user that must rely upon a filter for protection is often left with little or no direction to help understand a filters characteristics. Worse yet, many of the more common techniques for testing (and thus describing) filtration characteristics are misleading because they are totally unrelated to a filters application. A presentation of currently used filter test methods and newer, more applicable tests are discussed. Specific filter test procedures are recommended and application specific test programs are described as well.