Table 11 Sept 2026From “Forecast accuracy can hide offsetting errors”

The forecast-error cancellation trap

A zero mean signed error can hide a miss in every period when opposite errors cancel.

Table 1The forecast-error cancellation trap

Period	Actual outcome	Forecast	Signed error	Absolute error
1	100	80	-20	20
2	100	120	+20	20
3	100	80	-20	20
4	100	120	+20	20
Mean	100	100	0	20

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Source: Author's synthetic example. Values are illustrative and do not describe an observed forecast set.

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From the essay

Revenue operations & AI

Forecast accuracy can hide offsetting errors

A forecast can be unbiased on average while missing every period: keep signed error, absolute error, distribution, horizon, and decision cost separate.

1 Sept 2026

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APA 7

Isoglu, S. (2026). The forecast-error cancellation trap [Table]. isoglu.com. https://isoglu.com/insights/exhibits/isoglu-2026-forecast-accuracy-can-hide-offsetting-errors-fig02/

BibTeX

@misc{isoglu-2026-forecast-accuracy-can-hide-offsetting-errors-fig02,
  author = {Isoglu, Sinan},
  title = {{The forecast-error cancellation trap}},
  year = {2026},
  howpublished = {Table 1, isoglu.com},
  url = {https://isoglu.com/insights/exhibits/isoglu-2026-forecast-accuracy-can-hide-offsetting-errors-fig02/},
  note = {From the essay {Forecast accuracy can hide offsetting errors}}
}

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<figure>
  <a href="https://isoglu.com/insights/exhibits/isoglu-2026-forecast-accuracy-can-hide-offsetting-errors-fig02/">
    <img src="https://isoglu.com/social/isoglu-2026-forecast-accuracy-can-hide-offsetting-errors-fig02.png" alt="Table 1: The forecast-error cancellation trap" width="3200" height="2400">
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  <figcaption>Table 1: The forecast-error cancellation trap. Source: Author&#39;s synthetic example. Values are illustrative and do not describe an observed forecast set. <a href="https://isoglu.com/insights/exhibits/isoglu-2026-forecast-accuracy-can-hide-offsetting-errors-fig02/">View exhibit</a>.</figcaption>
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