The meaning of leaving someone back [ in American English ]

I just watched a great video (a kind of short documentary) about two educators who strive to afford better education for their students in a college in Red Hook (a neighborhood in Brooklyn).
The video makers made an interview with one of the students' mothers :

The mother (crying next to her son): I've never cried like this ... I've cried like this one time ... when I had to leave him back, and I cried, I cried, I cried, that was the hardest thing in my life, to tell his teacher to leave him back ... in third grade [...] I told his teacher to leave him back, because he was struggling.

I've looked up the meaning of leaving someone back on the web but, I didn't find a relevant meaning. Here is what I think it means :

The expression, leaving someone back (in the context of the interview): is to make someone stay in their current grade even if they succeed.

  • What do you guys think the meaning is? And is it common to use this "phrasal verb "?

You can find the video I saw the phrase used in here.


Solution 1:

Leave back or hold back means to make a child repeat a grade in school because of lack of academic progress, or very rarely, because of slow social and emotional development (usually in kindergarten or pre-school). Here's a transcript of an NPR show that uses the terms several times.

https://www.npr.org/2012/05/14/152683322/third-grade-a-pivotal-time-in-students-lives

The two terms are interchangeable, but hold back is far more common.
See Ngram chart below

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There is great debate in the US as to whether there is any merit in doing this, with intensive summer school classes seen as a better alternative by many.