He hould make a decision at the latest at the beginning of 2011.
He should make a decision at the beginning of 2011 at the latest.
Which sentence is better?
I'll hand in the assignment by the beginning of March. = I'll hand in the assignment before the beginning of March.
I'll hand in the assignment at the beginning of March. = I'll hand in the assignment during the first week or two of March.
Completely true but your sentence contains 'at the latest'. In this case, you're talking about any time upto a fixed point (not defined), aren't you? If so, 'by'. Would you be more likely to say:
'I'll be there at 6 at the latest'
'I'll be there by 6 at the latest'?
There is another reason why 'at' is not the best choice here:
'He should make a decision at the beginning of 2011 at the latest' - the emphasis here is making a decision 'at the beginning' but whether it's made at the beginning or some time before the beginning is irrelevant; what is relevant is that, you guessed it, it's made 'by' the beginning.
'at the latest' isn't redundant - it underlines that you won't go over that point. I still maintain that it is better to say:
by 6pm at the latest
by no later than 6pm
In the context of my work, I've certainly never seen 'this document must be signed on 31 December, 2010 at the latest'. The 'on' isn't important; the 'by' is.
Anybody else's opinion or a poll ?
I've asked a few colleagues and for what it's worth there's a pretty even split between:
I'll be back at 6 at the latest
I'll be back by 6 at the latest
So maybe I was wrong to say 'I'll be back by 6 at the latest' is preferable. Maybe it's either, or with a slight difference in emphasis. However, when it comes to the original sentence that was queried there's a unanimous 'by' from my colleagues. I've given my arguments why that might be - does anybody else care to disagree or comment?