As a lecturer, at the start of each semester in all of my courses, I have students complete a first-day diagnostic quiz on topics from the prerequisite course. There are usually a few significant under-performers (say, 40-50% success where most students are in the 70-100% range).
I then follow up with those under-performers by looking at their prior total course history. I always find a few cases that look like seriously troubled fits for their academic major. For example: Failing core courses one or more times and then passing with a "D" before repeating at the next level (e.g.: Introductory Programming for a C.S. major, Precalculus or Calculus I for a math major, etc.). Failing 5, 10, or 15 core courses over several years in the major (so far).
I feel like I want to do something to counsel these students, reflect on their choice of major, find the most profitable use of their time and resources, and/or find how to support or remove roadblocks if appropriate. But as the instructor, I'm not sure how best to do that.
One option would be to have a meeting in the first week and ask, "What difficulties can we improve on?", etc., so as to get off on the right foot and make the most of the time in the current term. Another option might be to say nothing until they likely fail my first exam and then use that as a wake-up call in the course.
How should I, as an instructor, intervene or counsel students who are struggling greatly with their major over a number of years?
(This is at a large U.S. community college.)