The duration of incoming quitline calls may serve as a crude proxy for the potential amount of reactive counseling provided.

To explore whether call duration may be useful for monitoring quitline capacity and service delivery.

Using data on the duration of incoming quitline calls to 1-800-QUIT-NOW from 2012 through 2015, we examined national trends and state-level variation in average call duration. We estimated a regression model of average call duration as a function of total incoming calls, nationally and by state, controlling for confounders.

From 2012 through 2015, average call duration was 11.4 min, nationally, and was 10 min or longer in 33 states. Average call duration was significantly correlated with quitline service provider. Higher incoming call volume was significantly associated with lower average call duration in 32 states and higher average call duration in five states (P-value <0.05). The relationship between call volume and call duration was not correlated with quitline service provider.

Variation in average call duration across states likely reflects different service delivery models. Average call duration was associated with call volume in many states. Significant changes in call duration may highlight potential quitline capacity issues that warrant further investigation.