The questionable claim
A report replaces a missing campaign spend with 0 and claims free conversions.
Investigate
Identify the unit of analysis, denominator, population or information boundary. What extra evidence would be needed? Write a corrected statement first.
Diagnosis and repair
Keep unavailable cost separate from known zero. Suppress spend-dependent rates until the amount is verified; flag the missing source and document its reporting impact.
Prevention
Add a test or review question that catches the error before publication. Save the original and corrected explanation so your reasoning is auditable.
Try the activity before reading its reference. Keep your sources, commands and assumptions with your work. Companion activities are unsaved self-practice and do not award a certificate or change lesson progress.