Use weighted averages in campaign reports
Combine rates without giving a small campaign disproportionate influence.
Add the counts before dividing
Campaign A receives 50 clicks from 1,000 impressions, or 5%. Campaign B receives 300 from 10,000, or 3%. Combined CTR is 350 divided by 11,000, about 3.18%. An average of 4% incorrectly weights both campaigns equally.
Use the right weight for each metric
Weight CTR by impressions, conversion rate by its eligible denominator, and CPA by conversions when recomputing from campaign costs. The safest approach is to add compatible numerator and denominator totals, then divide.
Show the mix when the blended rate changes
If more impressions move to Campaign B, the blended rate can fall with both individual rates unchanged. Report segment counts and rates to distinguish redistribution from a creative or audience problem.
Try a related tool
Measure clicks per impression. Use the same click type, placement scope, and date range across comparisons.
