CRO vs paid search (PPC): comparison, budget split guidance, and when each wins.
PPC buys traffic at variable per-click cost. CRO multiplies the value of every visitor (paid or organic). Running CRO alongside PPC reduces effective customer acquisition cost — paid traffic conversion lift carries through to PPC ROI directly.
CRO wins when conversion-rate is the binding constraint on revenue — that is, when the site has reasonable traffic but low conversion. Symptom: rising traffic, flat revenue. Diagnosis: conversion bottleneck. Treatment: CRO investment.
paid search (PPC) wins when traffic is the binding constraint — that is, when conversion is reasonable but traffic is low. Symptom: high conversion rate, low absolute revenue. Diagnosis: traffic bottleneck. Treatment: paid search (PPC) investment.
For most clients running both: depend on which constraint is currently binding. Typical starting blend: 60-70% paid search (PPC) investment for traffic + 30-40% CRO for conversion when traffic is the bottleneck; reverse when conversion is. Re-evaluate quarterly as the binding constraint shifts.
Almost always — they compound. The question is the budget split, not the choice.
Start where the binding constraint is. If traffic is low, fix traffic first. If conversion is low, fix conversion first.
Look at the funnel: high traffic + low conversion = CRO bottleneck. Low traffic + high conversion = traffic bottleneck. Both low = both bottlenecks (start with whichever has faster ROI in your context).