A Marketing Qualified Lead (MQL) becomes a Sales Qualified Lead when the sales team confirms that the contact actually fits the ideal customer profile, has the authority or access to the budget required, and is far enough along in the buying process to make a conversation worthwhile. The call from MQL to SQL belongs to sales — it is their evaluation, not a threshold crossed automatically.
The MQL-to-SQL handoff is one of the most diagnostically valuable interfaces in B2B sales. When the lead scoring system is well calibrated, sales accepts a high share of passed MQLs. When the acceptance rate is consistently low — many leads flagged by marketing, few accepted by sales — the cause is rarely a motivation problem. It is almost always a data quality or score definition problem sitting upstream.
The underlying problem in most underperforming MQL-to-SQL pipelines is not the handoff mechanism itself. It is that the scoring threshold was configured at a point in time — when a particular customer profile was the target — and was never recalibrated after products, markets, or ideal customer definitions shifted. Sales begins rejecting leads not because the process changed, but because reality changed and the model didn’t keep up.