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The Media Stack

How Mather Economics’ Subscription Proficiency Index (SPI) Helps Publishers Increase Engagement & ARPU

At the INMA Subscription Summit in March, I attended a seminar by Mather Economics, where they introduced their SPI methodology. This framework is designed to boost publisher revenues and APRU.

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The Media Stack
Apr 12, 2025
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In today’s rapidly evolving media landscape, digital subscriptions have become the cornerstone of sustainable growth for news publishers. Yet, while many organisations are investing heavily in digital transformation, far fewer have a clear, consistent way to measure the effectiveness of their efforts across the full subscriber journey.

Mather Economics’ Subscription Proficiency Index (SPI) — a strategic performance framework designed specifically for publishers. It offers a powerful, data-driven approach to diagnosing, tracking and optimising subscription performance over time.

What Exactly Is the SPI?

The Subscription Proficiency Index (SPI) is not a vanity metric or static snapshot. It’s a comprehensive scoring system that evaluates a publisher’s proficiency across the most critical aspects of digital subscription growth, assigning a performance score from 0 to 100.

The score is calculated using six key variables, each weighted by its importance to long-term subscription health:

  1. Audienc…

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