Solution 05 / Forecasting & Decision Models

Forecasts that change what someone actually does.

Demand and capacity forecasting, optimisation and scenario models, built around the decision they feed rather than the accuracy score they report.

Discuss Forecasting
01The problem

Most forecasting effort is spent improving a number that nobody acts on differently. Accuracy is tracked while bias goes unmeasured, so the forecast is wrong in the same direction for months without anyone noticing. Worse, the model produces a single point estimate when the decision it feeds needs a distribution: how much buffer to hold, how much capacity to book, how much risk to carry. A mean is the wrong input for a decision whose costs are asymmetric.

Typical symptoms

  • Forecast accuracy reported monthly, with no record of any decision it changed
  • Bias never measured, so the same directional error repeats for months
  • A single point forecast used for decisions that need a range
  • Manual overrides applied routinely, with no check on whether they help or hurt
  • No naive baseline, so nobody can say whether the model beats last week repeated
  • Backtests run on random splits, quietly leaking future information into the past
  • Intermittent and slow-moving items forced through the same method as steady ones

Decisions we help you make

  • Which decision the forecast exists to serve, and at what horizon and granularity
  • Point estimate or full distribution, given how asymmetric the cost of being wrong is
  • Which series are forecastable statistically and which need human judgement
  • What method fits each demand pattern: smooth, erratic, intermittent, or lumpy
  • Where human override adds value and where it destroys it
  • How forecasts reconcile across a hierarchy of product, location, and period
  • What the decision rule is that converts a forecast into an action
02How we work on it

Methods we apply.

Decision-first framing: define the action and its cost asymmetry before choosing a loss function

Naive and seasonal-naive baselines, so every model must beat the trivial answer

Demand classification and forecastability scoring before method selection

Probabilistic forecasting: quantiles and prediction intervals, scored with pinball loss and interval coverage

Rolling-origin backtesting that respects time order and prevents leakage

Bias and Forecast Value Add analysis across each step of the process, including overrides

Hierarchical forecasting with reconciliation across product, location and time

Optimisation and scenario modelling where the decision is constrained, not just predicted

When being short costs more than being long, the decision is taken from a quantile, not the average. A model that only reports a mean cannot answer the question the business is actually asking.

A forecast chart showing historical actuals followed by a forecast with a widening prediction interval. Two levels are marked: the mean forecast, which most models report, and the ninetieth percentile, where a decision with asymmetric costs would actually be set.

03What moves

Metrics this work is measured on.

WAPE / MAPE against baselineForecast biasForecast Value AddPrediction interval coverageOverride rate and override valueThe downstream decision metric: service level, cost, or utilisation
04What we need to start
  • History by series and period, ideally 24 months or more
  • The decision this forecast feeds, and who makes it
  • Known drivers: promotions, pricing, events, capacity constraints
  • Current forecast and override history, if the two can be separated
  • What it costs to be wrong in each direction
05Engagement path

How this becomes an engagement.

01

Forecast Review

2 weeks

Benchmark current accuracy and bias against naive baselines, and establish whether the forecast is changing any decision.

02

Forecasting Build

6–14 weeks

Build the pipeline, method selection, backtesting harness and decision rule, then run it against held-out periods.

03

Monitoring Handover

Ongoing

Bias, drift and value-add monitoring your team owns, with retrain and escalation thresholds already tuned.

Want to see what this looks like against your own systems?

Most engagements start with a short, fixed-scope assessment, enough to quantify the opportunity before anyone commits to a build.

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