These are the smallest family and the easiest to use correctly, which is why the mistakes with them are so consistent. “In conclusion” tells the reader you are about to close, and that promise binds you: what follows must restate, not extend. A new reason arriving after “in conclusion” is a claim with no paragraph behind it, and it damages the essay backwards by making the reader wonder why it was not argued.
The second consistent error is using one of these to close a paragraph rather than the essay. “In conclusion” at the end of Body 1 tells the reader the essay is finishing when two paragraphs remain. The word for closing a paragraph is different — “for this reason”, “this suggests that” — and the confusion produces an essay that appears to end three times.
The third is quantity. One concluding marker, once, at the start of the final paragraph. “In conclusion, to sum up, finally” is three signals for one paragraph, and each one weakens the others.
One marker, in the final paragraph. Not at the end of Body 1, and not three of them together.
A fresh reason after “in conclusion” arrives with no paragraph supporting it.
“For this reason” and “this suggests that” close a paragraph. “In conclusion” closes an essay.
It promises two sides were weighed, so the essay has to have weighed them.
