这句话有语法错误吗？（this sentence has any grammar mistake?）
The author in the passage advocates that the interview-centered method is much more accurate than the observation-centered approach, as the arguer got a result, that children in Tertia were reared by biological parents rather than an entire village by interviewing, is totally different from what Dr. Field got, twenty years ago, by observing. how to change to make the sentence more appropriate?

Question

这句话有语法错误吗？（this sentence has any grammar mistake?）
The author in the passage advocates that the interview-centered method is much more accurate than the observation-centered approach, as the arguer got a result, that children in Tertia were reared by biological parents rather than an entire village by interviewing, is totally different from what Dr. Field got, twenty years ago, by observing. how to change to make the sentence more appropriate?

Answer

Omit the second "is". The result is a long-winded and difficult to follow sentence, although grammatically sound.

Answer

The author in the passage advocates that the interview-centered method is much more accurate than the observation-centered approach. The author's interviews resulted in finding that children in Tertia,  were reared by biological parents whereas Dr. Field's  observation results made  twenty years ago, found that  children in Tertia, were reared by the entire village.