Architecture de la Couche de Validation

The ValidationLayer (monitoring/validation_layer.py) provides real-time data sanity checking on provider responses before metrics are exposed via the API.

Contrôles de Plage (FIELD_RANGES)

Every incoming numerical metric is validated against absolute domain boundaries:

Nom du Champ	Minimum Autorisé	Maximum Autorisé	Unité / Description
pe_ratio	-500.0	2000.0	Ratio PER (Price to Earnings)
dividend_yield	0.0	0.40	Rendement du dividende (0% à 40%)
beta	-5.0	10.0	Beta du marché
roe	-5.0	5.0	Rendement des capitaux propres (ROE -500% à +500%)
roa	-5.0	5.0	Rendement des actifs (ROA)
market_cap	1,000,000	10,000,000,000,000	Capitalisation boursière en devise locale

Values falling outside these bounds are discarded and replaced with None.

Vérification du Consensus Inter-Providers

When 2 or more providers supply a numerical value for the same field:

1. La valeur médiane entre tous les providers en accord est calculée : M = median(V_1, V_2, ..., V_k).
2. Pour chaque valeur V_i d'un provider, la déviation en pourcentage absolu est calculée : deviation = |V_i - M| / M
3. If deviation > VALIDATION_OUTLIER_THRESHOLD (default 0.50 or 50%), V_i is flagged as an outlier, logged in provider_health_log, and set to None.