Purpose: College placement assessments in the USA have underperformed in predicting college readiness. This has prompted a wave of reforms to placement practices and policies. Recently, student preparation for placement assessments has come to the forefront as a means for enabling better evaluation of college readiness. In this study, the authors explored the effects of an intervention aimed at preparing students for precollege placement assessments. The intervention focused on the provision of mathematics discipline-specific literacy skills because demonstrating mathematical mastery depends on students' ability to read, understand and translate text into mathematical computations. Design/methodology/approach: In this study, the authors used a randomized control trial design. The design enabled the authors to draw causal inferences while examining the effects of a placement assessment preparation intervention on mathematics placement and course outcomes. The authors also examined the intervention's effect across incoming first-year college students with varying levels of readiness. Findings: Findings demonstrated a positive and significant effect on assessment scores and placement for intervention participants with a stronger effect for those with higher levels of readiness. Intervention participants exhibited comparable academic success outcomes as those who did not receive the intervention. Originality/value: Little assessment research has explored the intersection of mathematics and literacy skills in relation to college readiness assessment. In addition, findings support the utility of preparation for college placement assessments.