Sarah McCarthey's current focus is on preparation of teachers to teach writing in K-12 schools within global contexts including Greece, Hong Kong and Singapore. Previous studies focused on the impact of professional development on teachers' writing instruction. She collected data on 20 teachers' writing instruction, philosophies of writing, and perceptions of professional development. In her work investigating teachers' attitudes towards writing and their writing instruction within policy contexts such as NCLB, she has identified trends in writing instruction including the implementation of writer's workshop, genre-based instruction, and skills approaches. She has also documented the importance of access to high-quality professional development for teachers to make changes in their writing instruction. Sarah is also actively involved in conducting research on teachers' and students' use of the online writing environment, Scholar. She is particularly interested in the nature of the feedback students provide peers and how they use that in their revisions.

Sarah was P. I. on the project "u-learn.net: An anywhere/anytime formative assessment and learning feedback environment" funded by the Institute of Education Sciences, U.S. Department of Education, Small Business Innovation Research Program. This project corresponded with her work as a consultant on the Assess-As-you-Go Project with Bill Cope as P.I. The projects focus on innovation in assessment in writing as students engage in writing and peer review in technology environments.

Sarah was co-editor with Mark Dressman and Paul Prior of Research in the Teaching of English, a premier journal in the field of literacy, between 2008-2013. She is Project Investigator of the University of Illinois Writing Project and Co-Director with Scott Filkins (Champaign Unit #4). The project brings together local teachers to improve writing instruction in grades k-12.