What do you mean (by) "more advanced"?

[Pirulo1234]

Hello everyone,

I've just read this dialogue:

- That price was based on a more advanced design
- What do you mean more advanced?

My question is... wouldn't it have been more correct to say "what do you mean by more advanced?"?

Thanks a million.

 

[Bevj]

What do you mean, more advanced? me parece totalmente correcto, pero con la adición de la coma.

 

[The Newt]

I agree with Bevj. In writing I would include "by," but in spoken English it's fine to leave it out.

 

[Cenzontle]

I would suggest quotation marks:
What do you mean, "more advanced"?