More the 1.46 million people in the United States have hearing losses in sufficient severity to be considered deaf; another 21 million people have other hearing impairments. For many deaf and hard-of-hearing individuals, sign language and voice interpreting is essential to their participation in educational programs and their access to public and private services. However, there is less than half the number of interpreters needed to meet the demand, interpreting quality is often variable, and there is a considerable lack of knowledge of factors that contribute to successful interpreting....