Paid Search
Smart Bidding
Smart Bidding is Google Ads' set of automated, machine-learning bid strategies that optimise toward goals like target CPA or target ROAS in each auction.
It adjusts bids using signals such as device, location, and time that would be impossible to manage manually. For example, Maximise Conversions automatically sets bids to win the most conversions within budget. It performs best with reliable conversion tracking and enough data to learn from.
Smart Bidding is a contract: you supply truthful conversion data and realistic targets, it supplies per-auction optimisation no human can match. Both clauses bind. Feed it soft conversions and it optimises toward noise; set a target CPA far below what the account has ever achieved and it simply stops entering auctions. Transitions cost two to four weeks of erratic learning, so change one thing at a time and judge on 30-day windows, never daily. Portfolio strategies help small campaigns by pooling their data, and seasonality adjustments exist for the spikes the algorithm cannot foresee.
Example
A campaign moves from manual CPC to Target CPA at 600 baht. First two weeks: spend erratic, conversions down, the learning phase doing its work. Week six: 640-baht average CPA with bids varying per auction from 4 to 60 baht by hour, device and audience, adjustments no human could make at that granularity. The prerequisite was the 90 conversions a month the system learned from.
Frequently asked questions
- Which Smart Bidding strategy should I use?
- Match the goal: Maximise Conversions with a tCPA for lead gen, Maximise Conversion Value with a tROAS for ecommerce. The prerequisite is honest conversion data at sufficient volume, roughly 30 conversions a month before target-based strategies stabilise.
- Why did Smart Bidding suddenly spend erratically?
- Learning resets: significant edits to targets, budgets, or conversion definitions restart the phase, and spend swings while it re-explores. Change one variable at a time, keep targets within reach of history, and judge on 30-day windows.
Related terms
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