Double your CTOR and increase email read rates over time with quizzes and NPS surveys — a Stripo case study

Gamification should increase engagement, but what happens when the gamification technique comes in as the seventh email in a seven-part sequence, and people have already fallen off before that point?

We did the experiment: a quiz game at the end of our educational sequence. At the same time, we tested a gamified NPS survey embedded directly into the body of the email, without having the recipient click out to an external form. The results surprised us, including the lowest unsubscribe rate in the entire chain.

Emails that we prepared

To bring our tests to life, we created an email chain with educational content about Stripo features. The whole chain consisted of seven emails, and the seventh one had a full-fledged quiz about what recipients learned with the whole email sequence. The quiz included six questions with four answers each, and only one answer was right. Pretty standard quiz structure.

Creating the quiz was a walk in the park, as we used our Stripo tools to create it. You can do the same, no technical knowledge required. For example, you can use our Multiple Choice Survey in the interactive module generator to create a full-fledged quiz or a survey with the required number of questions and answers in each in a matter of minutes.

Besides that, as a bonus, we decided to test an NPS survey in our emails, asking our recipients to review our guides, eBooks, and other content. Beyond the sporting interest in the effectiveness of this option, we were faced with the task of making this feedback channel more “vibrant,” so to speak. Instead of the usual CTA with a link to an external survey form, we added buttons that recipients can click to rate the content right in the email.

Designing surveys like this is also an easy task, since we have two types of surveys you can make using our interactive module generator: NPS survey and Product review. These interactive modules have slightly different designs, but they work almost identically, so you can pick the one that works best for your newsletter.

The results

We measured the performance of our newsletters with these interactive elements for seven months, so the results are pretty solid, and the things we achieved are quite impactful in terms of how they can change how you improve your email campaigns. We’ll break them down into sections so you’ll have a clearer picture of what we achieved.

General numbers

For the entire campaign with our quiz email, namely November 2025 to June 2026, we have the following numbers:

• 22.9% in terms of reads;
• an average CTOR of 2.09%;
• the unsubscribe rate is 1.31%;
• 24 fully completed quizzes.

Quiz achievements

Now let’s break down the numbers and what they mean. Our quiz email read rate was 22.9%, which is lower than in previous emails with feature lessons (27%-46%), but this is a completely normal situation. The email with the quiz was seventh in the chain, and it’s natural that some people had already been filtered out and did not reach it.

However, the remarkable thing is that the level of unsubscriptions for the email with the quiz was 1.31%, which was the lowest among all emails in the chain (the rest of the emails with lessons had around 1.5%-3.7%). This means that people who still followed the emails were not repelled by the gamification but rather retained.

Next, a little about the CTOR of the quiz. It was 2.09%, which was at the level of average emails with lessons in the chain (for example, lessons 3-5 had 2.0%-3.0%). This means that those who opened the email interacted with it no worse than with “regular” educational emails.

It’s also worth noting that the dynamics of the quiz email itself improved over time. In the first six months after our campaign launch, the read rate was 21.2%, in the last two months it was 26.8%, and CTOR also grew from 1.6% to 3.0%. This indicates that interest among recipients grew. We suspect that this may be due to word of mouth or to subscription lists “maturing.”

An email quiz doesn’t ‘eat up’ the audience at the end of an email chain. On the contrary, it’s the most loyal touchpoint in the entire sequence.

Oleksandr Dieiev,

Email marketing specialist at Stripo.

NPS survey achievement

Our NPS survey also produced pleasant results. Replacing the standard CTA with an interactive star rating directly in the email body transformed a potentially dead feedback channel (meaning only 1-2 inputs) into a working data collection tool. According to our figures, the first 20 ratings were found several months after the launch, without the need for additional clicking outside of the inboxes.

Wrapping up

From our small experiment, we can draw the following conclusion. Adding a gamified final test to an email chain did not cause audience churn; on the contrary, that email showed the lowest unsubscribe rate among the entire series and demonstrated growing engagement (CTOR almost doubled in the first months). The same can be said about interactive assessment and feedback options, such as NPS and the like. Gamification had a very positive effect on email performance, even if the gamified email was only one in a large chain and the last in the series.

Although we've already talked about the positive impact of gamification and interactivity on email performance, we decided to help you see this again with our own example. The results of this case study are excellent proof of their impact. And the best part is that quizzes and NPS questionnaires are among the simplest forms of interactivity, easily created with our help, without any technical knowledge. So, don’t hesitate to gamify your emails and boost their performance.