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Photo of three evaluators reviewing notes from a sign interview
Photo of sign classroom with instructor signing to faculty/staff class
Photo of three evaluators reviewing notes from a sign interview
at The National Technical
Institute for the Deaf


This section provides responses to frequently asked questions about the SLPI. These responses provide a description of the SLPI Rating Scale, discuss what the SLPI assesses, provide information about SLPI development, discuss where and with whom SLPI use has been implemented, and discuss other sign language assessment tools.

What Is the SLPI Rating Scale?
The Sign Language Proficiency Interview (SLPI) Rating Scale is a standard scale for rating sign language communication skills that is based on highly skilled, knowledgeable native-like signers. Since each SLPI candidate's performance is compared to this standard scale, not other candidates, the SLPI is a criterion referenced test.

More about the SLPI Rating Scale (pdf)

What does the SLPI assess?
The SLPI assesses a person's skills in using a natural sign language for communication (function) and it provides an analysis of a person's sign language vocabulary, production, fluency, grammar, and comprehension skills (form).

More about the SLPI assessments (pdf)

What is the history of the SLPI?
In 1980 at the Third National Symposium on Sign Language Research and Teaching in Boston, Protase Woodford from Educational Testing Services, Princeton, NJ, presented information about the Language/Oral Proficiency Interview, an interview technique for assessing spoken language communication skills. Based on Woodford's presentation, several individuals began to explore the application of interview techniques to the assessment of American Sign Language (ASL), including faculty from the College of Staten Island, Gallaudet University (then Gallaudet College), and the National Technical Institute for the Deaf (NTID). Our application at NTID was originally developed and piloted for evaluating the sign language communication skills of NTID faculty and staff, with the first formal implementation of the SLPI occurring for residential staff at the Louisiana School for the Deaf.

More about the SLPI history (pdf)

Where has SLPI use been implemented?
SLPI Training Workshops and implementation have occurred at more than 50 academic and vocational rehabilitation programs across the US and in Canada, Kenya, and South Africa.