What to Split Test First in a New Marketing Campaign

The Priority Framework

Not all tests are created equal. Some variables can swing your results by 30% or more, while others might produce a 2% improvement at best. When you are starting a new campaign and building your testing program from scratch, the order in which you test variables matters because your early tests set the foundation for everything that follows.

Think of your campaign as a funnel. The top of the funnel is whether someone opens your message. The middle is whether they engage with the content. The bottom is whether they take the action you want. Testing should follow the funnel from top to bottom because optimizing a later stage is pointless if the earlier stage is broken. A perfectly optimized landing page does not help if nobody clicks through to it.

Test 1: Subject Lines or Message Opening

Your first test should always address whether your message gets attention. For email campaigns, this means subject lines. For SMS campaigns, this means the first line of your text message. For social ads, this means the headline or hook.

The reason to start here is math. If your subject line test improves open rates from 20% to 26%, that is a 30% increase in the number of people who see your content. Every subsequent stage of your funnel benefits from this improvement. More opens means more potential clicks, which means more potential conversions, which means more revenue. No other test gives you this multiplicative effect on everything downstream.

Test 2: Core Offer or Value Proposition

Once you have a subject line that gets opens, test the main message itself. What are you offering? How are you framing it? This is typically the content of your email or the headline of your landing page.

Test fundamentally different approaches to your value proposition, not minor wording changes. Compare "save time" framing against "make more money" framing. Compare a specific claim ("reduce response time by 50%") against a general benefit ("deliver better customer service"). Compare a problem-focused message ("tired of losing leads?") against a solution-focused message ("convert 3x more leads").

These are big-picture tests that determine whether your core messaging resonates. Getting this right matters more than any formatting, design, or timing optimization because if your value proposition does not connect with your audience, no amount of button color testing will save the campaign.

Test 3: Call to Action

After you have a subject line that opens and a message that engages, test the action you are asking people to take. This includes the CTA button text, the type of action (download a guide vs. book a call vs. start a trial), and where on the page or in the email the CTA appears.

CTA tests are where you bridge the gap between interest and action. Someone who has read your email or landed on your page is already somewhat interested. The CTA test determines whether your ask matches their readiness to commit. A "Book a 30-Minute Demo" CTA might convert poorly if your audience is still in early research mode, while a "Download the Guide" CTA captures those early-stage leads effectively.

Test 4: Format and Layout

Once the fundamental messaging is optimized, test the presentation. This includes email format (text-only vs. HTML designed), email length (short and punchy vs. detailed and comprehensive), landing page layout (form above fold vs. below content), and the amount of visual content (image-heavy vs. text-focused).

Test 5: Timing and Frequency

Timing tests should come last because their impact is typically smaller than content and messaging tests. Test send day, send time, and campaign frequency. These optimizations squeeze out the final few percentage points of performance after the core elements are already performing well.

What Not to Test First

Avoid starting with low-impact tests like button color, font choices, or minor layout tweaks. These tests rarely produce meaningful results and they consume testing capacity that could be spent on high-impact variables. If your testing program starts with a button color test and produces an inconclusive result, the team may conclude that testing does not work, when the real problem is that they tested the wrong thing.