Attribution, incrementality or MMM: which method for which decision?

Attribution, experiment and MMM do not answer the same question. The selector offers a transparent teaching orientation; it replaces neither the framing of the estimand, nor the audit of the data, nor a scientific review.

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Measurement-method selectorTOOL / MEASURE-01

Choose one option per line. The result is educational orientation, not scientific validation.

Data
Experiment
Decision horizon
Question
Educational orientation

Marketing Mix Modeling + Triangulation

Tied at 8 points: weigh the methods against the cost of error, feasibility and the level of evidence required.

MethodScoreStatusUse
Marketing Mix Modeling8 pointstied orientationto validate
Triangulation8 pointstied orientationto validate
Experiment4 pointsalternativeto validate
Attribution2 pointsalternativeto validate
Explicit scaleTest feasible: +4 experiment, +2 triangulation; test difficult: +2 MMM. Rich data: +3 MMM, +2 attribution and +2 triangulation; limited data: +1 experiment. Fast horizon: +3 attribution; long horizon: +2 MMM and +2 triangulation. Full mix: +3 MMM and +2 triangulation; digital journey: +3 attribution.
Blocking conditionIf the population, intervention, comparator, outcome, horizon or comparability of the data are not documented, the score must not be used to commit to a method.

Educational orientation · the final decision is human

In depth

Understand the mechanism before using the tool.

Measuring marketing means estimating what would have happened without the action. The observed metric is not yet the causal effect.

The method depends on the decision, the grain, the horizon and the counterfactual available. Attribution, experiment and aggregate model answer different questions and must be triangulated.

01Unit of analysis

Define population, intervention, comparator, outcome and horizon before choosing the method: this is the estimand the analysis must actually identify.

02Horizon

Align the exposure period, the effect lag and the outcome window; guard against anticipation, contamination and carry-over effects.

03Comparison

Build the counterfactual explicitly: randomisation where possible, otherwise identification assumptions and verifiable diagnostics.

04Uncertainty

Report the interval, the power, the residual bias, the sensitivity and the economically relevant magnitude, not statistical significance alone.

05Decision threshold

A measurement becomes decisional when its interval separates the options and the plausible effect exceeds the cost and the risk of acting.

Points of vigilance

The distinctions that prevent a misreading.

01Attribution

It allocates an observed outcome according to a rule; it does not necessarily identify what marketing created.

02Incrementality

It compares the exposed outcome with the counterfactual outcome, controlling for systematic differences.

03Validity

Internal validity concerns the cause within the study; external validity concerns the transfer to other contexts.

Protocol

From framing to validation.

01State the estimand

Define population, intervention, comparison, outcome and horizon before choosing the method.

02Design the counterfactual

Randomise where possible; otherwise justify the identification assumptions and the diagnostics.

03Quantify the uncertainty

Report the interval, the power, the sensitivity and the economically relevant magnitude.

04Triangulate

Compare experiment, aggregate model, operational data and knowledge of the mechanism.

WORKED CASE

An observed ROAS can be far above the incremental ROAS

Situation. A campaign is credited with 1,000 conversions at €100 of margin, for €40,000 of spend. A test estimates that only 35% are incremental.

Calculation. Observed margin ROAS: 100,000 ÷ 40,000 = 2.5. Incremental ROAS: 35,000 ÷ 40,000 = 0.875.

Decision. Attribution describes where the conversions were recorded; the test changes the economic decision.

Adversarial review

Five questions to settle before presenting a recommendation.

  1. Is the unit actionable?

    Check that it matches the level at which a decision can be executed and tracked. A broader average can reverse the reading by hiding loss-making segments, channels or periods.

  2. Does the horizon cover the mechanism?

    Recompute the conclusion over a short window and a long one. Immediate costs, retention, saturation and delayed effects do not materialise at the same time.

  3. Does the comparator really represent the absence of action?

    Explain what would have happened without the decision. A historical trend or an attribution of contacts is not enough if selection, seasonality or simultaneous changes remain active.

  4. Which assumption tips the choice?

    Identify the parameter that changes the ranking, publish its plausible range and show the prudent scenario. A recommendation without sensitivity hides its main risk.

  5. Who stops or revises the decision?

    Name the owner, the observed signal, the threshold and the review date. Without a stopping rule, a favourable pilot easily becomes a permanent, unexamined commitment.

Acceptance conditions

What must be true before acting.

  • Write down the causal quantity sought before the analysis plan.
  • Report statistical uncertainty and the threshold of economic relevance.
  • Never mix attributed and incremental conversions in the same ratio.

Limits

What the analysis does not prove.

  • An underpowered experiment does not prove the absence of an effect.
  • Contamination between groups reduces the measurable difference.
  • A local, short result does not automatically transfer to every market and horizon.

References

Works used to frame the method.

  • Rubin, D. B. (1974), “Estimating Causal Effects of Treatments in Randomized and Nonrandomized Studies”.
  • Holland, P. W. (1986), “Statistics and Causal Inference”, Journal of the American Statistical Association.
  • Lewis, R. A. & Rao, J. M. (2015), Quarterly Journal of Economics.

Evidence status

What was not reproduced.

The power and sample-size calculations of the incrementality source were re-run without substitution: 6 of the 8 values it publishes are reproduced to the digit, the other 2 within 1.2% and 1.9% — a gap of the order of the tolerance its own method declares. Its campaign data and empirical results were never published and cannot be re-run. On the mix-model side, the data generator was executed, but neither the training, nor the figures, nor the empirical conclusions are reproduced. The method selector remains educational.