Dr. Pfeffer is a member of the American Sociological Association, Scholars Strategy Network, Sociologists for Women in Society, and the Diversity Scholars Network. In her local community, Dr. Pfeffer applies her research training and skills as a member of the Haslett Public School District Diversity, Equity, and Inclusion Leadership Team. Her nationally and internationally-recognized peer-reviewed research findings have been presented at venues such as: the American Sociological Association, Chicago Ethnography Conference, Council on Contemporary Families, European Professional Association for Transgender Health, Feminist Research Group, Hawaii International Conference on Social Sciences, International Congress of Qualitative Inquiry, International Sociological Association, Midwest Sociological Society, National Women's Studies Association, Pacific Sociological Association, Society for Social Work and Research, Sociologists for Women in Society, Southern Sociological Society, and World Professional Association for Transgender Health.

Dr. Pfeffer has been invited to deliver keynote addresses, guest lectures and research talks at: Columbia College, Drexel University, Duke University, Francis Marion University, Georgia State University, Harvard University, Indiana University (Bloomington and South Bend), Michigan State University, Newberry College, Northwestern University, Purdue University (North Central), RTI International, Syracuse University, University of California-Berkeley, University of Illinois, University of Leeds, University of Massachusetts Amherst, University of Michigan, University of Nebraska at Lincoln, University of South Carolina (Upstate and Columbia), University of South Florida, and University of Texas at Austin. She has served as: an invited peer reviewer for over 80 academic journals and presses; an invited advisory board member, external reviewer, and examiner for numerous university, national, and international grants, fellowships and awards, dissertations, and faculty promotion, tenure, and third-year review cases; an editorial board member for 10 journals; and is currently editor-in-chief of Fat Studies: An Interdisciplinary Journal of Body Weight and Society. 

Dr. Pfeffer's collaborative research projects involve focus on chest-binding practices among transgender and non-binary populations, healthcare providers specializing in the care of transgender and non-binary patients, and transgender and non-binary college students' experiences with university health services. She served as co-investigator on the project, "Trans Pregnancy: An International Exploration of Trans Male Experiences and Practices of Reproduction," (PI: Sally Hines, University of Sheffield). For this project, funded by the Economic and Social Research Council, Dr. Pfeffer conducted all study interviews and focus groups for the United States and Canada. In an ongoing mixed-methods project, she investigates two distinct populations in the era of the "obesity epidemic": 1) college students and their attitudes about fatness and 2) fat-acceptance advocates and activists. Dr. Pfeffer juxtaposes data from these sources to explore how attitudes about weight, weight management attempts, and disclosures about these attitudes and attempts, simultaneously reflect and fissure notions of responsible social citizenship, health, and sociopolitical group membership.

Her earlier work includes collaborative research examining Americans' beliefs about the potential genetic etiology of perceived gender, race, class, and sexual orientation differences and their associations with beliefs about the existence of group-directed prejudice, discrimination, and social inequalities.