"According to one estimate, the average American would have watched 22,000 hours of television by the time he or she has reached the age of sixteen." Why is the grammar error "would have watched"?

Question

anonymous · Answer

"Would have watched" implies the past tense--something you did NOT do but would have done if things were different. Like, "I would have let the dog out this morning if it was not raining."
This question needs to be in the future because it WILL happen eventually (by the time kids are 16), so it should read "will have watched" (will happen in the future) instead of "would have watched" (did not happen in the past).

anonymous · Answer

He's right. Saying 'will have' corroborates with the fact that this is an estimate. Estimates are a guess for the future or an unknown variable. If the sentence used 'would have', then it would indicate it happened in the past and then it wouldn't be an estimate anymore. If that makes sense?

anonymous · Answer

thank you! :D This helps a lot.