Proficiency refers to the ability to perform an action or function. It refers to one's ability to use language for real-world purposes to accomplish real-world linguistic tasks across a wide range of topics and settings. ACTFL Proficiency Tests reflect and measure the candidate's ability to carry out these real-world tasks.
Differing from an achievement test, which measures knowledge of specific information (what a person knows), a proficiency test targets what an individual can do with what he or she knows. As in a driver's test, an achievement test would represent the paper and pencil questions on the written examination, while a proficiency test determines how well the person can drive the car. The language proficiency test is an evaluation of how well a person can use language to communicate in real life.
ACTFL proficiency tests compare a person's unrehearsed ability against a set of language descriptors. These guidelines categorize proficiency along a continuum from the very top of the scale (full professional proficiency) to the very bottom (little or no functional ability). Each of the ten levels of proficiency outlined in these guidelines define language abilities in terms of tasks, text type, accuracy, and content areas. A rating on the proficiency scale does not consider how many semesters or years someone has been learning a language, what textbooks or other materials they have used, or even a speaker's knowledge of grammar – but rather is solely based on the speaker's demonstrated ability to use language to accomplish real-life tasks. Achievement tests, in contrast, typically focus on what an individual has learned based on the specific content or subject matter of what has been taught, and tend to be limited in scope to a specific textbook or curriculum.
Unlike an achievement test, in which it is possible to "get all the answers right," a proficiency test does not allow for a "perfect score," nor does it compare the results of the test to those of other test takers. In proficiency tests, one's performance is compared to a set of criteria, as defined in the ACTFL Proficiency Guidelines 2012.