In-Housing Marketing Effectiveness

Building an owned decision capability. A practical guide to turning models, experiments, data and judgement into better marketing investment decisions, without pretending uncertainty disappears.

Tyedal field guide ≈ 25 min read Updated August 2026

The assessment is the diagnostic from the guide, made interactive: one decision, eight dimensions, ten trade-offs, and a plan for where to start. Four minutes, no email needed to see your result.

The numbers arrived. The decision did not.

Picture a new CMO who has just joined a business. They do not actually need four ROIs. They need to set next year’s marketing budget, with finance in the room, under uncertainty that will not go away. What they get is a platform-reported cost per acquisition, a more conservative attribution number, a Marketing Mix Model estimate nearly half that again, and an old incrementality test that was quietly shelved because nobody liked what it said. Each number was expensive to produce. None of them can be used to choose between the alternatives on the table.

This is usually when in-housing gets discussed, as if the problem were where the model lives. The more useful question is whether the organisation owns the capability behind the decision: the questions, the evidence standard, the right to change the plan, and the learning that follows. Execution can still be hybrid. Ownership is not the same as doing every task internally.

This guide helps you assess that capability, and build the one that is right for the decisions you actually have to make.

You probably need this if

  • You're getting materially different answers to the same question from different sources, and nobody owns reconciling them
  • Budget decisions are being made on data nobody fully trusts
  • Finance treats marketing effectiveness as a black box, or ignores it
  • Your measurement knowledge lives entirely in agency heads, with no internal counterpart able to challenge it
  • You're paying for several layers of measurement that don't talk to each other
  • You're planning to scale spend, add markets, or add brands, and your current setup won't stretch

What's inside

Eleven sections, roughly 25 minutes of reading, plus a decision capability assessment you can take now, and a one-page decision contract to print.

  1. 01 Why more measurement has not produced better decisions. Conflicting numbers are a symptom. The product is the choice they were meant to support.
  2. 02 What it actually means to own the capability. Own the decisions, data, evidence standards and suppliers. Execution can stay hybrid.
  3. 03 Which decisions need to be supported. A one-page decision contract: owner, alternatives, threshold, next learning.
  4. 04 Assessing decision and measurement maturity. Eight dimensions. The constraint on the decision, not the average, drives the plan.
  5. 05 Designing the evidence system. Method follows the decision: MMM, experiments, attribution, research, judgement, scenarios.
  6. 06 Auditing data, technology and skills. Calendar length is not a sufficient test. Variation, grain and the question matter more.
  7. 07 Build, Run, Trust. The operating model, and where an external partner still adds value.
  8. 08 Planning under uncertainty. Expected outcome, range, hurdle, downside, reversibility, robustness, value of further information.
  9. 09 Validation, learning and value of information. When another study is worth it, and when it is not.
  10. 10 A practical in-housing roadmap. Sequence the work so the first decision can actually be made.
  11. 11 Working with Tyedal. Build, run and trust an owned decision capability, not a permanent dependency.

Includes a printable decision contract, and sources: IPA, Binet & Field, Thinkbox, Lewis & Rao, and others.

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Take the maturity assessment

Name the decision, score yourself on eight dimensions, then work through the trade-offs that decide what to build first. You get your result on screen straight away.

Start the assessment Four minutes · No email required

Written from the inside

This guide reflects direct experience building a marketing effectiveness function from scratch in-house, as well as work on both the agency and client side of these decisions.

Want help applying this to your organisation?

We’ll give you an honest assessment of readiness, the questions worth answering first, and where Tyedal can accelerate without locking you into a black box.