This study tried to control for all the confounding factors, so it looked at children who were equally intelligent and from the same social-class background, so it seemed as if it was the reading which really helped those children go on and score better on those school tests later in their lives.
Este estudio intentó controlar todos los factores de desviación, por eso se tomaron niños igualmente inteligentes y de la misma clase social. Así que parecía que era la lectura lo que realmente ayudó a esos niños a seguir y sacar mejores notas en pruebas escolares más adelante en su vida.