Difference in meaning betweeen "has been" and "is"

Question

Here is a sentence I'd like to fully understand.

The main change has been the shift from domestic vacations to ones overseas.

I think this sentence is more likely to emphasize the duration even though there's nothing referring to it. It implies that the change started in the past and exists even now. So, it would be natural for a reader or listener to think this change is nothing unexpected.

The main change is the shift from domestic vacations to ones overseas.

This sentence is more likely to focuse on now. It doesn't matter if the change was the shift in years gone by. It just gives information emphasizing nothing.

I'd like to know if I'm right to think this way.

Thanks in advance.

Answer 1

The use of "has been" establishes that the changes are being viewed as occurring over some period of time. The phrase might be preceded by a phrase such as, "Looking at vacation trends over a 10-year period," and the emphasis is on the behavior of the trends themselves.

Using "is" suggests that the focus is right now, and might be used after "Comparing vacation statistics from 2004 and 2014," where the speaker is referring more to the statistics than the underlying data.

So I'd pretty much agree with you.

Answer 2

If you use "has been", the subject of your sentence is the 'shift'.

Here's a different sentence using the same grammar to make it clearer:

The apple was eaten by the monkey

This is the passive form of "The monkey ate the apple". Compare this to your second example, which uses the active voice:

The main change is the shift from domestic vacations to ones overseas.

The subject of this sentence is the 'change', instead of the 'shift', therefore the focus of your sentence is on something else.