5 Essential GA4 Metrics Every Marketer Should Understand

Introduction: Why Metrics Matter More Than Ever

Google Analytics 4 (GA4) has redefined how we understand website and campaign performance.Unlike Universal Analytics, which was largely pageview-focused, GA4 shifts the spotlight to events, user behavior, and engagement across devices and platforms.

This is great news for marketers who want deeper insights — but it also introduces a new layer of complexity.

Gone are the days of scanning bounce rate and pageviews to judge performance. Now, marketers need to know which metrics truly matter — and how to act on them quickly.

So where should you focus your attention?

👉 In this guide, we’ll break down 5 core GA4 metrics every marketer should understand — no analytics background required.

👉 And if you’re tired of checking dashboards every day, we’ll also show you how Mikrolo Smart helps monitor these metrics automatically with customizable alerts and smart rules.

Let’s dive in.

Sessions: The Starting Point of Every Visit

In GA4, a session is the foundation of user activity — it represents a group of interactions that happen on your website within a set period of time.

But here’s the catch: sessions in GA4 don’t work exactly like they did in Universal Analytics.

What changed in GA4?

• GA4 uses a new session_start event to define when a session begins.

• Sessions don’t automatically reset at midnight or after a campaign change.

• It’s more accurate — but also harder to scan at a glance.

Why Sessions Still Matter for Marketers

Sessions tell you how often users are visiting your site. It’s a basic metric — but it’s also one of the first signs that something’s wrong.

A sudden drop in session count? Could be a broken tracking tag, a traffic source outage, or even a slow-loading page that users bounce from immediately.

🚨 How Mikrolo Helps

With Mikrolo Smart, you don’t need to catch it manually. You can create custom GA4 alerts that notify you if session counts drop by a certain percentage — daily, hourly, or on your own schedule.

📥 Example:

This way, you're not logging into GA4 just to discover bad news — you're staying ahead of it.

Engagement Rate: The New Bounce Rate — and Better

In Universal Analytics, marketers spent years tracking bounce rate. In GA4, engagement rate replaces it — and frankly, it’s a big upgrade.

What is Engagement Rate?

Engagement rate measures how many sessions were actually meaningful.A session is considered “engaged” if the user:

• Stays on the site for 10 seconds or more,

• Views 2 or more pages, or

• Triggers a conversion event.

The result is a far more useful metric than just “did they leave immediately?”

Why It Matters for Marketers

Engagement rate tells you if your content, landing pages, and user journey are working.If this number drops, your message probably isn’t landing — or users are frustrated.

Use it to track:

• Landing page quality

• Campaign targeting accuracy

• User interest across different channels

🚨 How Mikrolo Helps

You don’t need to manually compare engagement rate week over week.

With Mikrolo Smart, you can create custom alerts when engagement rate drops significantly — for a specific page, campaign, or traffic source.

📥 Example:

Instead of finding this out in a monthly report, you know right when it happens — and fix it fast.

Events: The Building Blocks of GA4

In GA4, everything is an event — from a simple pageview to a complex conversion.This is the biggest shift from Universal Analytics, and it gives marketers far more flexibility and insight.

What Is an Event in GA4?

An event is any action a user takes on your website or app.Examples include:

• page_view

• scroll

• click

• form_submit

• video_start

• purchase

You can track both default (automatically collected) events and custom ones that align with your goals.

Why It Matters for Marketers

With events, you’re not limited to just traffic numbers — you’re tracking actual user behavior.

Use events to:

• Understand what users are interacting with

• Track engagement with CTAs, videos, buttons, etc.

• Define custom micro-conversions (like PDF downloads or outbound link clicks)

Events help you move beyond “how many people came?” to “what did they actually do?”

🚨 How Mikrolo Helps

Not every event needs to be checked every day — but some are critical. With Mikrolo Smart, you can:

• Monitor key event counts (like form_submit, add_to_cart, or signup)

• Get real-time alerts when activity on important events drops or spikes

• Avoid discovering issues too late

📥 Example:

This could mean a broken form, a traffic mismatch, or UX friction — and with Mikrolo, you catch it the moment it matters.

Conversions: The Metrics That Tie to Business Goals

While traffic and engagement are important, conversions are where marketing impact becomes measurable.In GA4, you define what counts as a conversion — and that gives you control.

What Is a Conversion in GA4?

A conversion is any event you manually mark as important.It could be:

• A purchase

• A sign-up

• A form submission

• A “thank you” page view

• A key action in a funnel

Unlike Universal Analytics, where goals were predefined and limited, GA4 lets you choose any event as a conversion — giving you flexibility that maps directly to your business KPIs.

Why It Matters for Marketers

Conversions are your performance indicators.They tell you what’s working, what’s not, and where budget or creative may need to shift.

Use conversions to:

• Track results from campaigns

• Measure return on ad spend (ROAS)

• Understand user behavior across touchpoints

• Report value, not just volume

How Mikrolo Helps

Mikrolo Smart doesn’t just track conversions — it watches them.

You can set rules to alert you when:

• Conversions drop below a set threshold

• A campaign that normally performs well starts slipping

• A specific landing page stops converting

📥 Example:

This kind of alert means you can troubleshoot immediately — instead of discovering it in a monthly report when it’s too late.

Users vs New Users: Reach vs Retention

Understanding how many people visit your site is important — but knowing who they are is even more powerful.

GA4 gives you two key user metrics:

👥 Users

The total number of people who visited your site in a given time frame.

🆕 New Users

The number of people visiting for the first time.

Why It Matters for Marketers

This distinction helps answer critical questions:

• Are your campaigns attracting new audiences?

• Are returning users engaging more or less over time?

• Is your traffic growing — or just recycling?

For example:

• A spike in new users? Great — your awareness campaigns may be working.

• A drop in returning users? Maybe your site isn’t giving people a reason to come back.

🚨 How Mikrolo Helps

With Mikrolo Smart, you can set up alerts when user patterns shift significantly.

📥 Example:

This could signal a campaign issue, SEO drop, or a loss in referral traffic — and Mikrolo helps you catch it early.

Conclusion: Don’t Just Track — Act on What Matters

GA4 gives you access to more data than ever — but that’s only helpful if you know where to look and when to act.

Focusing on these five core metrics:

• Sessions

• Engagement Rate

• Events

• Conversions

• Users vs New Users

…can help you stay grounded in what really moves the needle in your marketing efforts.

But here’s the challenge:Most marketers don’t have time to check GA4 dashboards every day.And by the time a drop in performance is noticed, it’s often too late.

That’s where Mikrolo Smart comes in.

✅ Set your own thresholds

✅ Get real-time alerts when metrics shift

✅ Automate how you respond — before budget is wasted or leads are lost

👉 Ready to monitor GA4 like a pro — without babysitting dashboards? Start with Mikrolo Smart or book a demo and see how anomaly alerts can change the way you work.