Quick Answer: The most reliable indicators are a growing gap between scored MQLs and closed-won conversion, longer time-to-first-sales-touch, and an increasing number of high-scored leads that stall or churn early in the pipeline. If the score is not predicting faster progression through stages, sales velocity is being throttled by miscalibration, overfitting, or a model that rewards the wrong behaviors.
A lead scoring model is slowing sales velocity when it creates friction between marketing qualification and actual purchase intent. The clearest signals are declining stage-to-stage conversion rates for high-score cohorts, longer average time spent in each pipeline stage, and a widening variance between predicted fit/intent and sales outcomes. Additional warning signs include sales teams ignoring score thresholds, excessive manual requalification by reps, and a high volume of high-scored leads that never convert into meaningful opportunities. In practice, the model is underperforming when it increases pipeline noise rather than compressing cycle time and improving prioritization accuracy.