There is a case study of literacy and prison libraries, including information on demographics with a discussion of "empowerment" published in 1993; here is the citation:
Shethar, A. (1993). Literacy and "Empowerment"? A Case Study of Literacy behind Bars. Anthropology & Education Quarterly 24(4):357-372.
From the abstract:
"A Chicano prison inmate's progress in a year-long literacy tutorial course demonstrates ways in which writing can negotiate and reorganize race, class, gender, and power identities for both tutor and student, and legitimize the student's voice, native language, and discourse stance. Through dialogue, the student progresses from the passive-learner role to a presentation of self as knowledgeable expert; from denial of his prison group-membership, he progresses to a critical analysis of the power structure it represents."
Literacy Behind Bars: Results From the 2003 National Assessment of Adult Literacy Prison Survey, from the IES National Center for Education Statistics might also help you:
