Voice API Guide


  1. What Is A Voice API And How Does It Work?
  2. Basic Voice API Knowledge
  3. Voice API Rules And Regulations
  4. How to Integrate a Voice API?
  5. Picking the Best Voice API Provider
  6. Creating Your First Voice API Campaign
  7. Measuring Your Voice Campaign’s Success
  8. Helpful Voice API Resources

How to Measure Your Voice API Campaign Success

Voice APIs are one of the most popular methods for communicating with customers, especially for companies that want to add a more personalized touch to their campaigns. But despite how useful voice API campaigns can be, their success comes from the concentrated efforts of companies strategically applying them to targeted audiences.

And to better enhance their strategies, companies must measure the success of each campaign. Metrics let companies know how well the campaign is connecting with customers and how it could be better improved in the future for maximum return on value. Measuring a campaign’s success is critical to your overall marketing and communication strategy.

Keep reading to learn more about how to measure your voice campaign to see whether or not it’s effective and to what extent, thereby also indicating how successful it is or could be.

Measuring Your Voice API Campaign Success

An effective voice calling API campaign is one that is deliberately crafted and sent to a specific audience, rather than one with a generic script that is sent to every subscriber. But no matter how much attention to detail goes into a campaign, without metrics to gauge success, companies are still essentially trying to blindly connect with customers.

Measuring your success is vital to learning how to better serve customers, create more effective campaigns in the future, and change your current campaigns to leverage opportunities for improvement. Below, we’ll discuss a number of methods you can use to measure how well (or poorly) your campaigns are performing.

Successful Deliveries

The rate of successful delivery for each campaign is one measurement of success. Though perhaps not insightful into the customers themselves, delivery rate is an effective way to gauge the abilities of your programmable voice API. To calculate your successful delivery rate, divide the number of delivered texts by the number of sent texts and then multiply that by 100 ([Delivered Texts / Sent Texts] x 100 = Successful Message Delivery Rate Percentage).

If you have a low successful delivery rate, there could be a number of causes. These include API message caps or poor network quality, carrier errors, and invalid or outdated subscriber contact information. Depending on the content of your campaign, it’s also possible that your campaigns are being caught by spam filters. To determine the issue, work through the possible causes one by one.

To preempt such issues, it’s best to invest in a voice API provider that is scalable, has a Tier 1 network, and offers a 99.9% uptime SLA. Additionally, check their offered features and ask about the ability to integrate future services, such as phone verification APIs.

(Pro Tip: Phone Verification APIs, when used in conjunction with Voice or SMS APIs, scrub contact lists and remove, update, and correct subscriber information as needed.)

For companies that want more detailed information, calculating open rates or interaction rates may be more useful. The open rate refers to the percentage of voice campaign messages that subscribers actually listen to and the interaction rate refers to the percentage of voice campaigns that users actually act on. Below are the equations for both:

Open Rate: (Opened Campaigns / Successfully Delivered Campaigns) x 100 = Open Rate Percentage

Interaction Rate: (Interacted Campaigns / Successfully Delivered Campaigns) x 100 = Interaction Rate Percentage

List Growth

One indicator of overall voice call API campaign success is the growth rate of your subscription list. Though this percentage doesn’t necessarily reflect the success of a specific campaign, it can show how well your campaigns are doing overall. However, you can measure list growth in between campaigns by comparing the number of subscribers before and after each campaign.

To calculate your list growth rate, divide the number of campaign opt-ins by the number of campaign subscribers and multiple that by 100 ([Campaign Opt-Ins / Campaign Subscribers] x 100 = List Growth Percentage).

Keep in mind, this won’t give you an entirely accurate reflection of your campaign’s success. There are a number of reasons for list growth, some of which are linked to campaigns and some of which may be entirely unrelated. List growth may also be supplemented by your company’s other marketing and communication efforts.

Churn Rates

Also known as your unsubscribe rate or attrition rate, churn rate refers to the number of users who unsubscribed during a campaign and make your contact lists shrink. Keep in mind, some shrinkage and growth is normal; contact lists naturally change over time. However, there are a number of campaign-specific reasons users may unsubscribe, which churn rates will reveal by suddenly spiking.

To calculate your churn rate, divide the number of opt-outs during a campaign by the number of subscribers at the start of the campaign, and then multiple that by 100 ([Campaign Opt-Outs / Campaign Subscribers] x 100 = Churn Rate). Like list growth, churn rates can be measured per campaign or over time.

Common reasons for spikes in churn rates include sending too many messages, sending sporadic messages, and sending poorly-timed messages. All of this annoys customers, as do voice messages that offer no value, are misleading, or resemble spam. The last of these may also result in a customer reporting you or filing a complaint.

Conversion Rates

Conversion rate refers to the percentage of users that followed through on your call to action (CTA) or other campaign directions. Though this may sound similar to an interaction rate, the key difference is that a customer completed the CTA rather than just starting it. To calculate your conversion rate, divide the number of conversions by the number of successfully delivered campaigns and then multiply that by 100 ([Conversions / Successfully Delivered Messages] x 100).

If you’re still confused, it may be useful to think of open rates, interaction rates, and conversion rates as being on a scale ranging from ‘good’ to ‘great.’ It’s good if a customer opens your voice campaign, and better if they interact with it in some manner, but the best outcome is if they fully complete your CTA and “convert.”

If you have low conversion rates, it’s possible that there is a key element missing from your web voice API campaigns. This is especially true if you have high open and interaction rates, but your conversion rates remain consistently low. Analyze your campaigns and see where you can add more value for customers. If needed, host focus groups or otherwise solicit feedback directly from users.

Rinse, Wash, Repeat

Data can be useful on its own, but it’s more useful when combined with other metrics over a long period of time. The more data you have, the easier it will be to compare a specific campaign against overall performance. You’ll also be able to see your company’s general metrics and identify patterns or trends that appear over time.

The specific term for such long-term data gathering is ‘rinse, wash, repeat.’ This refers to continuing to calculate the percentages discussed above for each of your campaigns, building your data bank until you have enough information to run more detailed reports.

Essentially, the more information you have, the better equipped your company will be to gauge the full extent of a campaign’s success and determine what steps, if any, need to be taken to improve its effectiveness.

Let’s start sending, together.