I have read an article on sciencedaily.com and noticed the use of past perfect.

(http://www.sciencedaily.com/releases/2011/10/111020024329.htm )

It is not clear to me why they used past perfect. Would it be ok to use past simple instead of : had improved = improved, had fallen = fell.

Professor Price and colleagues found significant changes in the IQ scores measured in 2008 compared to the 2004 scores. Some subjects had improved their performance relative to people of a similar age by as much as 20 points on the standardised IQ scale; in other cases, however, performance had fallen by a similar amount.


marix998Would it be ok to use past simple instead
Yes, but the past perfect makes, well, perfect sense. Emotion: smile

The IQ measurement was done in 2008. The changes (improving or falling) had happened before that - from 2004 to 2008. This is a typical use of the past perfect to indicate a time even farther in the past than a time in the past already referred to.

The use of past perfect is correct here as it tried to depict the changes in the IQ of two different groups of subjects' over a four year period between 2004 to 2008. Two past time periods and events - perfectly described by past perfect.
 CalifJim's reply was promoted to an answer.