“By the way” in formal writing

Question

Can I say "By the way" in an official document or professional meeting and other important/formal times?

I never saw any film which would include these words.

Answer 1

No, I wouldn't recommend doing so, as the phrase is informal. There are many formal alternatives you could use to make you sound more professional, some of those are:

it is worth noting
it might also be noted/observed

Answer 2

The phrase by the way is not especially informal, and you may freely use it in formal situations. However, if you wish to use a variant which is more formal, then you could use a substitute such as:

• Speaking of which,
• This brings to mind
• Apropos

Or one of the phrases mentioned in Rimmer's answer.

Answer 3

The problem with "by the way" is not that it is informal, it is that in almost every case it is meaningless, unnecessary filler. Leave it out.

Answer 4

I wouldn't recommend it. It will seem like you are sidetracking, and in important/formal times, you certainly don't want to sidetrack!

I don't know about the film thing, but certainly not in formal settings.

You'd probably have said something like:

Also, there is...

Answer 5

I wouldn't, especially if it's likely to go to more than one country — i.e. if it might be read by people who don't understand that "by the way" means "pay extremely close attention! This is the most important point!"