The authors report the contextualization of effect sizes within mathematics anxiety research, and more specifically within research using the Mathematics Anxiety Rating Scale (MARS) and the MARS for Adolescents (MARS-A). The effect sizes from 45 studies were characterized by graphing confidence intervals (CIs) across studies involving (a) adults not participating in studies focusing on remedial or entry-level mathematics students or teachers, (b) remedial mathematics and entry-level college mathematics students, (c) preservice and inservice teachers, and (d) 7-12th-grade students and rising college students. The results also illustrate how CIs can be useful in research syntheses, because CIs (a) encourage meta-analytic thinking, (b) provide information about the research precision of a literature, and (c) provide plausible estimates for parameter values even if initial research expectations are wildly wrong. (Contains 1 table and 6 figures.)