Evaluating Campaigns — KPIs, Test Duration, Budgets and Sensible Test Setups
Which KPIs actually matter, how long a test must run, how much budget it needs, and which setups deliver reliable answers — and which don't.
in Search Engine Advertising
CPC, CPM, CPV, CPA, CPL, CPO, CTR, CVR, ROAS, POAS, KUR, iROAS, View-Rate.
Advertising KPI: average cost per conversion. Central efficiency metric for lead gen and performance marketing, and the steering input for tCPA bidding.
Advertising KPI: ratio of conversion revenue to ad spend. Central steering metric in e-commerce and the input for tROAS bidding.
Advertising KPI: share of clicks (or sessions) that result in a conversion. Central efficiency metric for landing page and offer quality.
Advertising KPI: cost per click. In Google Ads, the primary billing model for Search and the key short-term efficiency lever for bidding.
Advertising KPI: share of impressions that result in a click. Indicator of ad relevance and a component of the Google Ads Quality Score.
Advertising KPI: ratio of gross profit to ad spend. Margin-aware alternative to ROAS, especially relevant for broad assortments and sale dynamics.
Advertising KPI: cost per generated lead. Standard efficiency metric for B2B and service marketing where the conversion is an inquiry rather than a purchase.
Advertising KPI: cost per thousand impressions. Standard billing model for Display, Video, and awareness campaigns where visibility is the goal.
Advertising KPI: cost per order. Standard efficiency metric in e-commerce, where an order is the typical conversion.
Advertising KPI: share of ad spend in attributed revenue, expressed as a percentage. Mathematical inverse of ROAS, common in DACH e-commerce reporting.
Advertising KPI: cost per video view. Standard billing for YouTube In-Stream skippable ads — paid only if the user watches at least 30 seconds (or finishes shorter videos).
Which KPIs actually matter, how long a test must run, how much budget it needs, and which setups deliver reliable answers — and which don't.
How CPC, CPA, CPL, CPO, ROAS, POAS, CIR, ROI, CTR and CVR fit together mathematically — with a reference table and concrete worked examples.