Table 3.

Individual difference measures

Feature	Summary
Gender	ASSISTments does not ask users to self-report gender. Gender is determined by comparing a user’s first name to a global name database from which gender is inferred. Gender may be set to “Unknown” if a user’s name is not found in the database.
Grade level	The student’s grade level. Although the Skill Builder used in the experimental methodology was designed for grade 8 students, any grade level teacher could freely assign the Skill Builder. For example, a teacher might have assigned it to challenge advanced students in lower grade levels, to provide practice for grade 8 students, or to review the relevant prior knowledge of students in higher grade levels.
Prior Skill Builder count	The number of prior ASSISTments Skill Builders a student has started to answer.
Prior Skill Builder completion percentage	The number of prior ASSISTments Skill Builders that a student completed out of all the Skill Builders he/she started.
Prior problem count	The number of prior individual ASSISTments problems that a student has answered.
Prior problem correctness percentage	The percentage of ASSISTments problems that a student has answered correctly out of all problems he/she answered, prior to participation in the studies.