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Validation measurement

As explained in Experimentation for Engineers

A measurement performed at an estimated optimal setting to check whether the predicted system outcome agrees with observed performance.

A validation measurement checks whether a predicted optimum agrees with observed performance before a production system adopts the new setting. Run the system at the estimated optimum, aggregate many individual outcomes, and compare the observed result with the prediction. section 4.1.5

Apply the procedure as follows:

  • Set the parameter or parameters to the values returned by optimization, such as threshold_opt and order_size_opt. section 4.1.5 section 4.2.2
  • Collect enough individual production measurements to estimate an aggregate outcome and its standard error; the examples use 15,000 measurements. section 4.1.5 section 4.2.2
  • Accept the estimate when it lies within the validation aggregate measurement plus or minus twice its standard error, an approximate 95% confidence interval. section 4.1.5 section 4.2.2
  • Return to experimental design when the estimate falls outside those bounds or when measurements reveal an outlier that violates the local model assumption. section 4.2.2

Two-parameter trading experiment

Optimization suggests threshold_opt = 1.12, order_size_opt = 3.0, and estimated maximum markout profit = 0.41. A validation run produces an aggregate measurement of 0.37 with standard error 0.026, giving [0.32, 0.43]. Because 0.41 lies inside this interval, the estimate is validated. section 4.2.2

Figure 4.12 Validate stage. In this final stage, you’ll run the production prop trading system at the optimal value of threshold that you estimated in the analyze stage. If the measured markout profit at that threshold is close enough (see the next section for discussion) to the estimated markout_profit(threshold), then you may accept the optimal threshold as the result of the RSM process.
04-12

Use the validation-stage diagram to follow the handoff from an estimated optimum to a production run and an accept-or-redesign decision. section 4.1.5

How Experimentation for Engineers covers it

How deep it goes
Defines repeated measurement, aggregation, standard error, and a 95% interval, but defers broader automated validation methods.
Examples
Uses trading thresholds, order sizes, markout profit, 15,000-run experiments, and a numerical two-parameter confidence interval.
What it assumes
Assumes optimization has produced parameter settings and an estimated outcome, while explaining the validation calculation itself.
What you can do after
Evaluate whether an optimized parameter estimate is plausible or whether the experiment should return to design.
How it connects
Connects response surface methodology with optimization, interpolation, standard error, confidence intervals, and experimental design.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Experimentation for Engineers. The section links point to the parts of the book it draws on.