What effect has Google's removal of advertising from the right hand side of its search results pages had on campaign spend and performance? There's quite a bit of data floating around that examines the development.
Kenshoo, for example, published results from research it conducted over the week following the Google change, finding a small (one percent) decrease in CPC (cost per click), and on the whole, week-over-week changes to click and spend volume were within normal weekly variance, with a small increase in clicks and a smaller increase in spending due to the drop in average cost per click (CPC).
Another study from Accuracast found that the click-through rate has increased on paid search results at the top of the results. Accuracast's data shows a large increase of 18.2 percent for ads in position 4, and increases for position 1 and 2 of 8.4 percent & 7.7 percent, respectively as well. The only ad position where the CTR dropped after the change was position 3.