As per Adword: Quality Score is an estimate of how relevant your ads, keywords, and landing page are to a person seeing your ad. Higher Quality Scores typically lead to lower costs and better ad positions. As per Adcenter : Quality Score is Measure of Campaign Competitiveness Now, I have 1 campaign with few ads, keywords and Landing Page. And have updated the same campaign in both adcenter and adwords. Now quality score for one keyword in Adword is 1 whereas quality Score for same keyword in adcenter is 8. Can any one tell me the reason behind variations? Is this because of Google search & Bing search (different search engines)
QS in both systems are calculated in similar ways. It's a comparison of your CTR to the historical CTR for the keyword taking into account the position. See my Adwords FAQ for more details. In Adwords, there is a portion for relevancy. They also use QS for policy compliance. If you don't comply with one or more rules, having a bridge page for example, your QS = 1 and is essentially an off switch. Don't expect QS on both systems to be the same. There are as said some differences in how they calculate it. The historical data used for one thing is different since they are two separate systems. Your own CTR will be different since the ads are different. Adwords has two description lines and Adcenter just one. Simply tacking the descriptions together in Adcenter does not guarantee the same level of success. They are in effect two different ads. You have to take into account the differences in both systems in how your ads are displayed.