Reach

Measured as

Measure Reach with a fixed attribution window, conversion event, and spend basis before comparing campaigns or creative tests.

Misused when

• Treating reach as guaranteed exposure (it can include low-quality placements).
• Comparing reach across platforms without aligning time windows.

Operator takeaway

• Use reach with frequency to understand how saturated an audience is.
• High reach with low frequency usually means you still have room to scale.
• Compare reach by segment (prospecting vs retargeting) to avoid mixing intent.
• Use Reach only inside a stable attribution rule, conversion definition, and time window so campaign comparisons stay honest.
• If performance changes, check whether the metric moved for a real business reason or because the measurement setup changed underneath you.

Next decision

• Read Frequency and creative fatigue: diagnose performance decay and fix it if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.
• Decide which report owns Reach before comparing campaigns, channels, or creative tests.