Glossary

Purpose

This glossary exists to reduce ambiguity. Many performance disagreements are not analytical — they are linguistic. Different teams use the same terms to mean different things.

The definitions below reflect how these terms are used in practice across e-commerce, paid media platforms, and growth advisory work.

Core Business & Growth Metrics

CAC (Customer Acquisition Cost)

The total cost required to acquire a new customer. In practice, CAC varies depending on attribution window, channel inclusion, and whether costs beyond media spend are included.

LTV (Lifetime Value)

The total gross contribution a customer is expected to generate over their relationship with the business. Often modeled rather than known with certainty.

Payback Period

The time required for gross profit from a customer to recover acquisition cost. A key constraint on growth velocity.

MER (Marketing Efficiency Ratio)

Total revenue divided by total marketing spend. Useful at the system level, but insufficient for diagnosing channel-level performance.

Paid Media & Platform Concepts

Account Structure

How campaigns, ad sets, and ads are organized. Structure influences learning, budget efficiency, and signal clarity.

Bidding Strategy

The mechanism platforms use to optimize delivery (e.g., cost cap, value optimization). Bidding affects who sees ads, not just how much is paid.

Creative Fatigue

Performance degradation caused by repeated exposure rather than market saturation. Often misdiagnosed as audience exhaustion.

Learning Phase

A platform state where delivery is still exploring outcomes. Frequent changes can prevent stable learning.

Incrementality

The degree to which media spend drives outcomes that would not have occurred otherwise. Difficult to measure directly in platform-reported data.

Measurement & Attribution

Attribution Window

The time period in which a conversion is credited to an ad interaction. Changing windows can materially change reported performance.

Platform vs Analytics Discrepancy

The gap between platform-reported results and third-party analytics (GA, Shopify, etc.). A signal quality issue, not necessarily an error.

Signal Quality

The reliability of events sent back to platforms. Affected by tracking design, browser restrictions, server-side implementations, and user behavior.

CAPI / Server-Side Tracking

Sending events from a server rather than the browser to improve durability and match quality. Not a cure-all.

Deduplication

Preventing the same event from being counted twice when using multiple tracking methods.

Funnels & Conversion

Funnel Leakage

Loss of users due to friction, confusion, or mismatch between stages (ad → landing page → checkout).

Offer Continuity

Consistency between ad promise, landing page message, and checkout experience.

Conversion Friction

Any unnecessary resistance in the purchase path — cognitive, technical, or experiential.

Decision & Systems Thinking

Constraint

The limiting factor preventing further growth. Often misidentified when data is noisy.

Local vs System Optimization

Improving one component (e.g., CPC) at the expense of overall system performance.

Decision Instrumentation

The quality of reporting and feedback loops used to guide action. Poor instrumentation leads to confident but incorrect decisions.

Attribution Risk

The likelihood that reported performance diverges meaningfully from reality due to measurement limitations.

Confidence Theater

The appearance of certainty created by precise dashboards and metrics that obscure underlying uncertainty.

How to use this glossary

These definitions are intended to serve as shared language. Alignment on meaning precedes alignment on strategy.