Well, as people are having questions about why some are getting NOIs and others are not (despite meeting the OINP eligibility criteria). I guess, this is worth mentioning:
B. From the pool of EE candidates meeting the OINP HCPS minimum eligibility criteria, maybe Ontario sends NOIs to those with higher program score i.e., the main IRCC selection criteria for FSWP & CEC (check page 28 of the guide):
Link: http://www.ontarioimmigration.ca/prodconsum/groups/csc/@oipp/documents/document/oi_en_hcps.pdf
And maybe, it's based on the six selection factors for FSWP, and those with higher score (out of 100), are sent NOIs first.
http://www.cic.gc.ca/english/immigrate/skilled/apply-factors.asp
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Anyways, if candidates can share their basic program score out of 100, those still waiting for an NOI can find out if there is any correlation and/or a pattern (just an idea).