Simple Past/Present Perfect

[Heidili]

Hello!

I was wondering whether any of the following sentences would be preferable to the others, is there a big difference between the two different tenses in these cases?

1) As I've already mentioned earlier ...
As I already mentioned earlier

2) In writing this I have tried ...
In writing this I tried ...

Thank you very much for your help

Heidi

[MrPedantic]

Hello Heidili

The difference is one of focus: when you use the present perfect, you make a connection between a past action and the present.

So in your second examples:

2a. In writing this I have tried ...
2b. In writing this I tried ...

2a suggests a present connection (perhaps you are still writing it), whereas 2b puts the "writing" firmly in the past (perhaps you wrote it a year ago).

MrP

[rewboss]

2a makes the text seem more "immediate" to the reader.

Another difference is that American English doesn't use the present perfect quite as often as British English. In the sentences you cite, the choice is more a matter of style than actual meaning (this isn't often the case in English), and in both cases British writers would use the present perfect, while American writers, especially in informal writing, would probably prefer the simple past.