sir,

how to determine seniority of a group A officer who joined in drdo by recruitment,but applied through proper channel (technical resignation at another purely central government office in group A cadre) with respect to his counterparts in DRDO?

1. Whether date of joining in govt service is considered ?
2. or date of joining in DRDO is considered?
3. please clarify by quoting relavent order

regards
gowrishankar