Marketing Contribution Return – Base-100 Rebase Report

Choose this endpoint when you need to express a series of marketing contribution return observations as an indexed series relative to a specific reference period, particularly for trend comparison, stakeholder reporting, or normalisation across different spend scales. It is purpose-built for this metric and returns the formula and units alongside figures, making it suitable for auditable or explainable analytics workflows. Prefer alternatives if you need raw ROAS, trend-line fitting, or benchmark correlation rather than index normalisation.

• Fewer than 2 rows supplied — minimum items constraint violated
• base_index references a row that does not exist in the submitted array
• marketing_spend value is zero or negative — exclusiveMinimum constraint violated
• Row objects missing required fields attributed_contribution or marketing_spend
• More than 200 rows submitted — maxItems constraint violated
• Base observation produces a zero denominator (zero contribution return at base point), preventing valid rebase