Where r ac is the correlation between age of paper and number of citations. Where r ah is the correlation between age of paper and number of hits. Where r ch is the correlation between number of citations and number of hits.
Older papers get less hits.
Papers with more citations get more hits. As the three values are all related it is possible to correlate two values and remove the dependance on the third by using a partial correlation technique. Where r ac-h is the correlation between age of paper and citations, excluding the effect that the number of hits would have on it. These 3 values are only slightly bigger in magnitude than the values with no excluded variables. For the graph below the papers where split based on the total number of citations extracted.