the growth is faster than estimated=?

[HJWSam]

The U.S. economic growth last year is slightly faster than initially estimated =

[1] The U.S. economic growth last year is slightly faster than it was initially estimated that it would be.
[2] ?The U.S. economic growth last year is slightly faster than it was initially estimated to be.
[3] ?The U.S. economic growth last year is slightly faster than the growth was initially estimated to be.
[4] ?The U.S. economic growth last year is slightly faster than initially estimated to be.

[5] *The U.S. economic growth last year is slightly faster than it was initially estimated.
[6] *The U.S. economic growth last year is slightly faster than the growth was initially estimated.

I think [1] is correct and [5][6] are incorrect, but I am not sure about [2][3][4].
I think [2] and [3]are the same, where 'it' in [2] is 'the growth' in [3], if they are correct expressions.

 

[Uncle Jack]

In general, we tend to use as few words as possible, so the most likely sentence is probably this:

[7] U.S. economic growth last year was slightly faster than initially estimated.​

Note that "the" is not used when "U.S." is being used as an attributive modifier, and that I have changed "is" to "was" because last year is in the past. Conceivably "is" is correct, but it would need context to justify its use.

Sentence [1] really is too wordy, with the repetition of "it", and sentence [2] is much better. [3] would not be used because people will wonder if "the growth" is something different from "U.S. economic growth". [4] would not be used because "to be" needs "it was".

In sentence [5], since you no longer have "to be", you don't need "it", but if you remove "it" you get a valid sentence. [6] has the same fault as [3].

 

[HJWSam]

In general, we tend to use as few words as possible, so the most likely sentence is probably this:

[7] U.S. economic growth last year was slightly faster than initially estimated.​

Note that "the" is not used when "U.S." is being used as an attributive modifier, and that I have changed "is" to "was" because last year is in the past. Conceivably "is" is correct, but it would need context to justify its use.

Sentence [1] really is too wordy, with the repetition of "it", and sentence [2] is much better. [3] would not be used because people will wonder if "the growth" is something different from "U.S. economic growth". [4] would not be used because "to be" needs "it was".

In sentence [5], since you no longer have "to be", you don't need "it", but if you remove "it" you get a valid sentence. [6] has the same fault as [3].

Thanks for your help.