CSULB describes its frosh admission eligibility index for fall 2021 admissions here:https://www.csulb.edu/admissions/freshmen-eligibility-index
California State University - Long Beach:
The CSULB Index for CSULB ranking is calculated as follows:
(College Preparatory Grade Point Average* X 200) + (500 x HS Math Subject GPA) + (500 x HS English GPA).
The STEM Index for CSULB ranking in STEM (Science, Technology, Engineering and Math) majors is calculated as follows:
600 x HS Math Subject GPA + 600 x HS Science Subject GPA.
It is not entirely clear whether the STEM Index is used alone for applicants to STEM majors, or is added to the CSULB Index for applicants to STEM majors.