Complex sentence: Some education psychologists accuse that the over-emphasis on academic performance is one of the reason behind the "Hong Kong Kids phenomenon" These parents usually belong to a group of "three highs"--high education, high income and high social status.
Split into simpler sentences: Some education psychologists criticized that the over-emphasis on academic performance is one of the factors leading to the "Kongkid phenomenon". The parents of the Kongkids usually belong to a group of "three highs"--high education, high income and high social status.