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The decisions that cost the most.

Short pieces on the defaults that quietly spend money in an Amazon Ads account, written from running one. Each ends where the behaviour is specified: the documentation.

What these are
One costly mistake each, with the arithmetic
What they are not
Tool comparisons, or a substitute for the docs
Figures
Worked examples, never a measured account

Articles

  1. Search terms

    Your negative keyword is not blocking what you think it is

    Why a term you blocked keeps taking spend, how to read the evidence before you block again, and what unnegation is for.

    6 min readSpecified in Negation and unnegate rule

  2. Bidding

    An ACOS threshold cannot tell $8 from $800

    What a fixed ACOS rule actually measures, why it fires hardest on the targets that matter least, and the arithmetic that fixes it.

    7 min readSpecified in Loss Budget Guard

  3. Evidence

    Ninety days will hide the fortnight that broke

    How averaging a window buries a target that stopped converting, and when to ask a question instead of setting a rule.

    6 min readSpecified in Evidence and periods

Every figure in these articles is a worked example written to explain a calculation. None of them is measured performance from any account, ours or anyone else's.

The reasoning is the product.

Read a Decision Brief against the account you already run, and apply it when you agree with it.