The current literature review highlights the need for a two-dimensional rating system for Mexican American acculturation. It demonstrates increased attention to acculturation issues over time despite ongoing lack of the two-dimensional acculturation analysis. Although creators of the Acculturation Rating Scale for Mexican Americans–II (ARSMA-II) originally stated that the measure’s Mexican Orientation and Anglo Orientation subscales were orthogonal, they combined the two into a unidimensional acculturation score. A review of usage of the ARSMA-II from 1995 to 2013 revealed that 56% of studies collapsed the two subscales into a single acculturation score. Additional analysis revealed an increase in studies using the ARSMA-II across time, while showing that there was neither a difference in the usage of unidimensional and bidimensional scoring methods nor a shift in choosing scoring methods across time. We recommend that future studies use both the Mexican Orientation and the Anglo Orientation subscales to increase the accuracy of their acculturation research.