How does the consular officer decide whether to grant a 1-year or 5-year F1 visa to Chinese students?

Question

I read on bu.edu/isso:

The U.S. Department of State (“DOS”) has issued guidance to consular officers in China that could result in shorter visas for a small number of Chinese students beginning June 11, 2018. While most Chinese nationals began receiving a multiple-entry F-1 student visa for a maximum of five years beginning November 14, 2014, graduate students who are studying in major fields related to robotics, aviation, and high-tech manufacturing may, at the discretion of the consular officer, now receive a multiple entry visa for a shorter 1-year time frame.

How does the consular officer decide whether to grant a 1-year or 5-year F1 visa to Chinese students?

Answer 1

The main source of information I can find is this AP news article from May 2018, which says:

The State Department did not provide specifics. But a U.S. official said that according to instructions sent to U.S. embassies and consulates, Chinese graduate students will be limited to one-year visas if they are studying in fields like robotics, aviation and high-tech manufacturing. China identified those areas as priorities in its “Made in China” 2025 manufacturing plan.