The Middle Grades Longitudinal Study of 2017-18 (MGLS:2017) measured student achievement in mathematics and reading along with executive function. The MGLS:2017 ILF contains the item level data from these direct measures that can be used in psychometric research for replicating or enhancing the scoring found in the MGLS:2017 RUF or in creating new scores. The Middle Grades Longitudinal Study of 2017–18 (MGLS:2017) Assessment Item Level File (ILF) contains two .csv files representing the two rounds of data collection: the MGLS:2017 Main Study (MS) Base Year (MS1) and the Main Study Follow-up (MS2) files.