In 2012, computer-based assessments in mathematics and reading were offered as optional assessments for participating education systems. Thirty-two education systems, including the United States, chose to administer them. In these education systems, a subset of students who took the paper-based assessment also took an additional computer-based assessment. Although the paper-based assessment items and the computer-based assessment items were derived from the same frameworks, there was no overlap in the assessment items between the two assessment modes. The interactive nature of computer-based assessment allowed PISA to assess students in novel contexts that are not possible with a traditional paper-based format. For instance, the computer-based mathematics assessment was designed to measure the same mathematics content and processes as the paper-based assessment, but the computer-based environment provided the opportunity to include tasks requiring students to manipulate mathematical tools like statistical software, geometric construction, visualization utilities, and virtual measuring instruments (OECD 2013, pp. 43–44). And, while individuals use many of the same reading processes and skills when they are reading print or reading online, there are reading processes that are unique to an electronic environment, such as navigation across multiple sites without explicit direction or using web-based navigation tools such as drop-down menus (OECD 2013, p. 80). The computer-based reading assessment was designed to investigate students’ proficiency in that context. For both mathematics and reading, the paper-based assessment and computer-based assessment were scaled separately. Therefore, scores on the paper-based assessment cannot be compared to scores on the computer-based assessment.