Which method is best suited for training a large group of personnel at once?

The best method for training a large group of personnel at once is the lecture. This approach allows a single instructor to convey information, concepts, and theories to many learners simultaneously, making it efficient in terms of time and resources. Lectures can cover a wide range of material in a structured manner, ensuring that all attendees receive the same foundational knowledge without the logistical challenges that smaller group methods might present.

While other methods like demonstration or discussion may be effective for smaller groups or specialized training, they typically require more interaction and participation, which can create challenges when managing a larger audience. Hands-on practice also necessitates more supervision and individual attention, which is not feasible in a large training session. Thus, the lecture stands out as the most practical option for disseminating information effectively to a large group at once.