Too short
A too short window may miss purchases that will not take place until later in the same buying cycle.
Glossary
Attribution Window
The attribution Window is the maximum time between a relevant search interaction and a conversion in which the link is still considered valid.
Too long
Too long a window increases the chance that a conversion will happen to be linked to an old search interaction.
Assortment counts
The appropriate duration differs between fast impulse purchases and products with a longer orientation phase.
Documenting
Establish the chosen definition and use it consistently in dashboards, audits and comparisons.