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Topic cluster / Regime detection and contextTest a context layer by comparing the same base strategy with and without the overlay under identical costs, timing rules, and out-of-sample windows. The real question is whether the layer improves net edge, drawdown behavior, or operating simplicity after the storytelling is stripped away.
What to remember
The clean test is base strategy versus base strategy plus context layer, with everything else held constant. If the overlay changes costs, timing, rebalance rules, or allowable leverage, those changes need to be counted as part of the overlay rather than treated like free upgrades.
This sounds obvious, but many context layers look good only because they quietly smuggle in a second policy change at the same time.
A good context layer does not have to boost every metric. It may improve net Sharpe, reduce crash exposure, or stabilize turnover. What matters is that the benefit is clear, repeatable, and worth the added complexity.
If the context layer only helps in sample, only in one market, or only under one threshold, you probably learned more about your own tuning than about the market. Walk-forward and rolling out-of-sample comparisons matter because context layers are especially good at sounding intelligent after the fact.
The last check is operational. Once the overlay is running forward, does it still behave like the research promised, or does it mostly create extra state changes, harder debugging, and new excuses for why the current period should not count?