Ratio Dialing

Ratio dialing is an outbound dialing approach where a fixed number of lines are dialed for every available agent, maintaining a constant ratio regardless of changing call center conditions. It is functionally similar to power dialing and is often used interchangeably with that term in VICIdial contexts.

How It Works in VICIdial

Ratio dialing in VICIdial is implemented through the auto dial level setting. A ratio of 2:1 means two lines are dialed for each waiting agent, configured by setting the auto dial level to 2.0. The available_only_ratio_tally setting is critical here — it determines whether the ratio is calculated against agents in the “waiting” state only, or against all logged-in agents including those on active calls.

When available_only_ratio_tally is set to “Y” (recommended), a 3:1 ratio with 5 waiting agents dials 15 lines. When set to “N,” the same ratio with 20 total agents (but only 5 waiting) would dial 60 lines, potentially causing massive abandon rates. This distinction is one of the most common misconfiguration errors in VICIdial campaigns.

Why It Matters

Ratio dialing is best suited for campaigns where the manager wants direct, predictable control over the dialing pace. It is simpler to understand and configure than adaptive dialing, making it a good choice for smaller operations or teams new to automated dialing. The fixed ratio also makes it easier to predict trunk utilization and plan carrier capacity.

However, ratio dialing cannot respond to changing conditions automatically. If your list transitions from a high-answer-rate time zone to a low-answer-rate zone, the fixed ratio will not adjust. For campaigns running more than a few hours across multiple time zones, adaptive dialing is generally the better choice. See the predictive dialer settings guide for ratio recommendations by campaign size.