> ## Documentation Index
> Fetch the complete documentation index at: https://wiki.platelunchcollective.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Return on Investment

> Return on investment is the gain from an expenditure measured against its cost, the ratio marketing programs answer to and the hardest thing to trace in AI search.

*Measurement* · *Fractional CMO*

## Definition

Return on investment is the gain from an expenditure measured against its cost, the ratio that says whether money spent produced more value than it consumed. In marketing it asks a blunt question of any program: did the revenue or pipeline it generated exceed what it took to run. It is the frame every other marketing metric eventually answers to.

## Why It Matters for AI Search

AI-search work invites the same question as any marketing investment, and it is a fair one to ask. The difficulty is attribution: a recommendation made inside a model's answer, acted on days later, leaves a fainter trail than a clicked ad. Measuring return here means tracking the marks that do get left, citation presence, referral patterns, the movement of high-intent traffic, and reasoning from them rather than from a single clean number. Customer acquisition cost sits on the cost side of the same ledger.

## Related Terms

<CardGroup cols={2}>
  <Card title="Customer acquisition cost" href="/ai-search-glossary/cac">See also</Card>
  <Card title="Share of model" href="/ai-search-glossary/share-of-model">See also</Card>
  <Card title="Answer engine ranking" href="/ai-search-glossary/answer-engine-ranking">See also</Card>
  <Card title="Fractional CMO" href="/ai-search-glossary/fractional-cmo">See also</Card>
</CardGroup>

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