The Quality score is the result of a benchmark where the traffic on your campaign is compared to traffic on AudienceReport campaigns similar to yours.
A score between 8 and 10 is a good Quality score. This means that your campaign is among the best performing campaigns in the benchmark.
A score between 6 and 8 indicates that your campaign is underperforming in the benchmark. In this case, it is recommended to compare quality metrics against your own expectations from the campaign, as it might still be performing well in the redefined context.
A score under 6 means that your campaign is performing badly in the benchmark and you should explore the quality metrics to get some insights into why this is happening.
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