Email marketing has always been a game of precision. The right subject line, sender name, email content, or even the send time can make or break your campaign’s performance. For years, marketers have relied on A/B testing to improve email engagement, but there’s a more advanced, data-driven approach: Multivariate testing. If you’re still sticking to A/B testing, you might be missing out on significant opportunities to optimize your campaigns.
In this guide, we’ll explore why email testing is crucial, how multivariate testing is an upgrade to A/B testing, and the exact steps to conduct successful Multivariate tests using Kasplo, the platform that makes advanced testing seamless and effective.
“What’s the best, fastest, and most reliable way to grow your email and SMS marketing performance?”
A/B Testing
performance.
Founder @ AJ Media | Scaling eCom brands with Email & SMS
Why testing email campaigns is important
No two audiences are the same, and email marketing is not a one-size-fits-all strategy. While best practices provide a good starting point, actual user behavior often deviates from theoretical assumptions. Testing helps uncover what really works for your audience.
Here’s why testing your emails is non-negotiable:
- Higher engagement rates
Small tweaks in subject lines, email design, or call-to-action (CTA) buttons can lead to significantly higher open rates and conversions.
- Data-driven decision making
Instead of guessing, multivariate testing lets you make decisions based on actual subscriber behavior, reducing wasted efforts.
- Personalization & segmentation
You can identify which variables resonate with different audience segments, leading to better personalization and improved customer relationships.
- Improved deliverability
Email providers monitor engagement metrics. Higher open and click rates help improve sender reputation, ensuring your emails don’t end up in spam.
- Competitive edge
With email inboxes more crowded than ever, optimizing your content based on real insights gives you an edge over competitors still relying on intuition.
How multivariate testing is different
A/B testing is simple but limited. You compare two variations of an email and send them to a small sample of your audience. The better-performing version is then sent to the remaining list. While this works, it doesn’t allow for testing multiple variables at once.
Multivariate testing is like A/B testing on steroids. It allows you to test multiple variations simultaneously in Kasplo. This means you can experiment with multiple subject lines, sender names, and CTAs in one test, rather than running separate A/B tests over time.
Benefits of multivariate testing in Kasplo
- Multivariate Analysis: Test multiple elements at the same time (subject line, sender name, CTA, email content, etc.).
- Faster Insights: Get results in one go rather than running multiple A/B tests.
- More Accurate Data: A/B testing may not capture subtle variations, while multivariate testing helps determine the best possible combination.
- Higher ROI: The more optimized your email campaigns, the better your revenue per email sent.
- Seamless Execution: With Kasplo’s multivariate testing feature, you can easily set up, analyze, and implement tests without any technical complexity.
8 Steps to conducting successful multivariate testing for emails
- Step 1: Define your goal
Before testing, be clear on what you want to achieve. Are you optimizing for:
- Higher open rates? (Test subject lines and sender names in Kasplo)
- More clicks? (Test CTA buttons, email layout, and copy variations)
- Better conversion rates? (Test offers, email personalization, and imagery)
- Step 2: Identify variables to test
Unlike A/B testing, multivariate testing allows for multiple changes. Here are some variables worth experimenting with:
- Subject Lines: Does personalization (“Hey {Name}!”) work better than curiosity-driven lines?
- Sender Name: Should emails come from a person or a brand?
- CTA Placement & Design: Does a button work better than a text link? What color grabs attention?
- Email Copy Length: Do concise emails convert better than long-form storytelling?
- Images vs. No Images: Does an image-heavy email impact click-through rates?
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- Step 3: Create multiple variations
With Kasplo’s multivariate testing, you can create up to 10 email variations in one test. For example, if testing subject lines, you can create:
- Subject Line 1: “Boost Your Sales with This Simple Trick🚀”
- Subject Line 2: “Your Sales Strategy is Missing This One Thing”
- Subject Line 3: “How We Increased Revenue by 47% (Case Study)”
- Subject Line 4: “Quick Question About Your Business Growth”
- Step 4: Select your sample size
Kasplo helps you determine the right sample size for statistically significant results. Ideally, 10-20% of your total email list should be included in the test.
- Step 5: Choose a winning metric
Your goal determines which metric decides the winner:
- Open Rate (if testing subject lines or sender names)
- Click Rate (if testing CTA buttons or email layout)
- Conversion Rate (if testing overall content and offers)
- Step 6: Set test duration
Allow enough time to gather meaningful results, usually 4-24 hours depending on your audience size and engagement patterns.
- Step 7: Analyze results & send winning version
Kasplo automatically tracks test results and picks the highest-performing variation. Once the test is complete, Kasplo will automatically send the winning version to the rest of your email list.
- Step 8: Document findings & apply insights
Testing is an ongoing process. Kasplo provides detailed reports on what works best for different campaigns, helping you continuously optimize future emails.
What no one tells you about multivariate testing
Multivariate testing can uncover unexpected insights
Sometimes, variables you assume won’t matter can make a huge difference. A brand once discovered that removing emojis from subject lines doubled open rates.
- Small changes can lead to big wins
Even minor tweaks, like changing a CTA from “Shop Now” to “Get Yours Today,” can significantly impact conversions. - Testing too many variables can be counterproductive
While multivariate testing is powerful, testing too many elements at once can make it hard to pinpoint what actually worked. Prioritize the most critical variables. - Timing is just as important as content
The best subject line in the world won’t help if you’re sending emails at the wrong time. Combine multivariate testing with send-time optimization in Kasplo for better results. - Keep Iterating, A winning formula today might not work tomorrow
Consumer behavior changes, so keep testing regularly to stay ahead.
“Most A/B tests fail because they’re either set up wrong or the data isn’t understood properly.”
@jamesketchall
Final thoughts
Email marketing success is no longer about guesswork, it’s about precision, data, and continuous improvement. Multivariate testing gives you the power to go beyond A/B testing and truly understand what resonates with your audience. By testing multiple variables at once, you get deeper insights, faster optimizations, and ultimately, higher engagement and conversions.
At Kasplo, we make multivariate testing effortless. Our platform allows you to test multiple email versions, track real-time performance, and automatically optimize for the best results. Whether you want to refine subject lines, personalize sender names, or experiment with content layouts, Kasplo’s advanced testing and automation tools help you craft emails that your audience loves.
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