The importance of test order in external and standardized test results: The case of PISA 2018.

Standardized tests intend to reduce information asymmetry by providing a common and objective measure of students' academic performance. The basic assumption underlying standardized testing is that differences in student performance on standardized tests should be attributed primarily to differences in the quality of education received by students. However, there is evidence that environmental factors can affect standardized test scores, which may result in anomalous observations or outliers that show a distortion of student performance.