How do I choose a click lookback window that isn't just an arbitrary default?
Measure your own click-to-book delay and set the window where the curve flattens. Pull a few hundred closed jobs, compute the days between first tracked click and booking, and find the point where additional days stop adding meaningful volume. Emergency repair work usually flattens within days. Replacement, install and remodel work runs far longer, and often deserves a different window.
The window is a fact about your business
Default windows exist because platforms need a number, not because that number describes you. A drain cleaning company and a whole-home generator company have nothing in common in this dimension, and both are handed the same default.
The window is doing one job: deciding how far back a touch is still allowed to claim influence. Set it too generously and you credit clicks that had nothing to do with the sale. Set it too tightly and real influence disappears into direct traffic.
Building the curve
You need two timestamps joined on one lead: the first tracked click and the booking. That join is the hard part and it is why this analysis is rare — it requires the ad-side session data and the operational record to share an identifier, which is the core of a field service integration.
Once you have the pairs, plot the cumulative share of bookings by days elapsed. Nearly every business shows a steep early rise and a long thin tail. Put the window where the curve visibly bends, not where the tail finally ends.
One account, several windows
Most operators discover their business contains two or three distinct curves. Emergency work books within hours. Planned replacement books over weeks. Financed or permitted work books over months. Averaging them produces a window that fits none of the segments.
Where the platform allows it, separate campaigns by job intent so each can carry an appropriate window. Where it does not, choose the window that fits the segment carrying the most revenue and note the distortion for the others in your channel reporting rather than pretending it is not there.
What each error costs you
A too-long window inflates assisted conversions, makes upper-funnel and brand activity look better than it is, and creates double counting across channels that each claim the same eventual job. A too-short window strands legitimate influence in unattributed traffic and systematically undervalues anything that works early in the journey — usually the channels that build demand rather than harvest it.
Neither error announces itself. The only way to notice is to run the same period at two window lengths and compare the channel table. If nothing meaningful moves, your window choice is not the thing limiting your reporting.
Topics: lookback window · sales cycle · measurement · segmentation
Have a version of this question about your own business?
The useful answer usually depends on which systems you run and how they're connected. That's a conversation, not a blog post.