Hi all,

I work in advertising and have a question (as the answer looks wrong and therefore must be)... I have been told it is Simpson's paradox, but don't agree, so here it is; if my cost per thousands by title have remained static, why is the weighted CPT change not 0%?

Circulations
Supplier Previous Circulation Current Circulation Circulation Change (%)
Magazine A 30,000 25,000 -16.7%
Magazine B 150,000 100,000 -33.3%
Supplier Insertions 2011 Rate 2011 Spend 2011 Impacts 2011 CPT
Magazine A 8 1,500 12,000 240,000 50.00
Magazine B 4 2,000 8,000 600,000 13.33
TOTAL 12 3,500 20,000 840,000 23.81
Supplier Insertions 2012 Rate Rate change (%) 2012 Spend 2012 Impacts 2012 CPT CPT change (%)
Magazine A 8 1,250.00 -16.7% 10,000 200,000 50.00 0.0%
Magazine B 4 1,333.33 -33.3% 5,333 400,000 13.33 0.0%
TOTAL 12 2,583 -26.2% 15,333 600,000 25.56 7.3%