To investigate how readability affects the way adults who are learning to read evaluate health information, a mixed methods research study was designed based on a sociotechnical framework and using theories of everyday life information seeking. The study analyzed a corpus of consumer health information documents (N = 501) using the CohMetrix text analysis tool (McNamara, Graesser, McCarthy & Cai, 2014) and a set of NLP-based tools developed by Educational Testing Service (ETS) called SourceRater and Language Muse® to identify specific linguistic features that contribute to readability. In this study, these tools were used to assess the difficulty of reading health information. In the next phase of the study, adults who are learning to read (N = 20) assessed the readability of the documents in the corpus as part of a usability study. The study found that the documents' low narrativity, limited concept and word overlap, and low cohesion contribute to the difficulty of reading health information for adults who are learning to read. It also identified differences in perceptions of reading difficulty among adults who are learning to read. The findings highlight the limitations of current health literacy guidelines and of using readability formulas like the Flesch-Kincaid Grade Level formula to determine the readability of consumer health information, and questions the reliability of "Easy to Read" health information collections. Health information documents that are easier to read can improve access to health information that supports and addresses the needs of communities with poor health outcomes, including adults who are learning to read. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]