CBSE is using Theory Evaluation Trend Analysis (TETRA) software to analyse the trend of marks being obtained by the students across regions. In case of any deviations from the norm, the board gets in touch with that center to find out if there were any complaints regarding any ambiguity or difficulty in the question paper.

TETRA was used by CBSE last year to verify all quarters after the maths and economics papers of class 10 and 12 were leaked last year. It was found that class 10 students did not benefit from the maths paper leak as the score graph matched the trend.

Source: https://www.indiatoday.in/education-today/news/story/cbse-board-exam-2019-board-to-use-tetra-software-to-balance-difficulty-level-1454361-2019-02-12