This is the document that explains it:
https://docs.google.com/document/d/1CBV-EdM_af3s2TzUmQr4T8bA9kMYMZ-L96jRM2spKDA
Basically, as part of SIPPI/GT identification, the parent input form is one of three possible behavioral sources, along with teacher and school staff input, where, if a threshold is met, there is a lower threshold among the cognitive measure (CogAT, if at the grade levels given) and academic measures (DIBELS/Lectura, MAP, MCAP -- depending on grade level).
Though similar academic measures (MAP & grades) are used for central identification for the criteria-based magnet lotteries (4th/5th grade CES, the Humanities MS programs and the Math/Science/Computer Science MS programs), the processes for that are separate from the GT identification process, which is state-mandated (but with MCPS-defined criteria). One correlates with the other, but is not influenced by the other.
For reference:
CES FAQ --
https://docs.google.com/document/d/1k0D-Z3uAc8ydu4P7gegUxkKMsV2_dDbbP-hnIB-oTjA
Criteria-based MS Program FAQ --
https://docs.google.com/document/d/1-cnoWQ61gfF2ybNI8ReXSV-AhTh5oQqhGzX0tCTqqkk
General Pages:
Special Programs --
https://www.montgomeryschoolsmd.org/curriculum/specialprograms
Accelerated & Enriched Instruction --
https://www.montgomeryschoolsmd.org/curriculum/enriched