Table 220 Aug 2026From “Marketing mix modeling is a calibration problem”

The calibration log

A model becomes more credible when its assumptions and outside anchors are visible in the same row.

Table 2The calibration log

Model element	Assumption	External anchor	If the anchor moves
Baseline demand	The non-media demand path has this shape	Control series, category data or known interruption	Re-estimate the base before reallocating
Carryover	Exposure persists for this long	Delayed response in an experiment or prior with a stated basis	Widen the scenario range
Saturation	Additional spend produces less response after this point	Spend variation with an independent shock	Do not use the point estimate as a ceiling
Channel interaction	Two channels reinforce or substitute	Designed test or a documented mechanism	Keep the interaction as a scenario, not a fact
Incremental lift	The allocation reflects causal contribution	Holdout, ghost-ad or lift result	Mark the model coefficient as uncalibrated

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Source: Author's worksheet for documenting what enters a marketing mix model and what anchors it outside the model.

PNG4:3, 1600 × 1200, with the title, the source line and the attribution set in the image isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02.png

From the essay

Growth that compounds

Marketing mix modeling is a calibration problem

Marketing mix modeling can organise an aggregate budget, but it cannot certify causality by itself. Calibrate the model before trusting the allocation.

20 Aug 2026

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APA 7

Isoglu, S. (2026). The calibration log [Table]. isoglu.com. https://isoglu.com/insights/exhibits/isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02/

BibTeX

@misc{isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02,
  author = {Isoglu, Sinan},
  title = {{The calibration log}},
  year = {2026},
  howpublished = {Table 2, isoglu.com},
  url = {https://isoglu.com/insights/exhibits/isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02/},
  note = {From the essay {Marketing mix modeling is a calibration problem}}
}

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<figure>
  <a href="https://isoglu.com/insights/exhibits/isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02/">
    <img src="https://isoglu.com/social/isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02.png" alt="Table 2: The calibration log" width="3200" height="2400">
  </a>
  <figcaption>Table 2: The calibration log. Source: Author&#39;s worksheet for documenting what enters a marketing mix model and what anchors it outside the model. <a href="https://isoglu.com/insights/exhibits/isoglu-2026-marketing-mix-modeling-is-a-calibration-problem-fig02/">View exhibit</a>.</figcaption>
</figure>