In digital advertising, getting your message in front of the right audience at the right time is everything. But how do you know it actually happened? That’s where ad delivery metrics come in.
These KPIs help marketers verify that campaigns ran as intended: ads were served, seen (by real people), and interacted with.
With so many platforms, partners, and fraud risks in the mix, tracking ad delivery is both a major opportunity and a potential minefield.
In this post, we’ll break down what ad delivery is, why it matters, and which ad delivery metrics are essential for digital marketers to monitor.
What is ad delivery?
Ad delivery refers to the actual fulfillment of a digital media campaign: the impressions, clicks, and ad interactions that occurred once the campaign went live.
Some of the most basic delivery signals - like actual delivery (how many impressions were served) and ad requests (how many times an ad was called for) - provide a starting point.
They establish whether your campaign is running, and at what scale. But to really understand the effectiveness and integrity of your delivery, you’ll need to look deeper.
Why does this matter to marketers?
Ad delivery is where your media budget turns into visible outcomes - or fails to. Tracking ad delivery metrics ensures you’re reaching real audiences, verifying scale, and holding platforms accountable for the inventory they claim to serve.
Without tracking ad delivery correctly, you risk overpaying for underperformance, missing technical issues, or letting fraud slip through undetected. Marketers who track ad delivery well can optimize in real time, improve campaign reliability, and build more trust with stakeholders.
Which ad delivery metrics should marketers be tracking?
Here are 10 ad delivery metrics that provide the clearest picture of campaign execution and scale:
1. Billing impressions
What is it?
The number of impressions that meet platform standards for being billable, such as viewability and fraud filters.
Why is it important?
Billing impressions are the ones you pay for. They represent impressions that meet viewability standards, fraud filters, or brand safety requirements. Tracking them helps validate vendor charges and understand how much of your delivery is "high quality."
2. Total net clicks
What is it?
Valid user clicks, after filtering out invalid and duplicate activity.
Why is it important?
Total net clicks help you understand real engagement. It filters out noisy or fraudulent interactions, giving you a more accurate picture of whether your ads are generating interest.
Here's the formula:
Total net clicks = Gross clicks − Invalid clicks − Duplicates
3. Clicks (SIVT)
What is it?
Clicks that were removed due to Sophisticated Invalid Traffic (e.g., bots or malicious activity).
Why is it important?
Clicks (SIVT) point to how much of your traffic might be wasted or misleading. High SIVT means you’re potentially spending money on bots instead of people - never a good look for performance.
4. Default clicks
What is it?
Clicks on a default ad that appears when targeted creative isn’t available.
Why is it important?
Default clicks can signal missed targeting or creative setup issues. If your system’s showing placeholder ads, it’s likely you’re not getting the experience you intended in front of users.
5. Fill rate
What is it?
The percentage of ad requests that result in an ad being served.
Why is it important?
Fill rate is all about efficiency. A low fill rate means you're missing opportunities - possibly because of tight targeting, low bids, or platform errors. Monitoring this helps you optimize delivery against available supply.
Here's the formula:
Fill rate = (Impressions ÷ Ad Requests) × 100
6. Matched impressions
What is it?
The number of impressions served to the correct audience or format as per campaign setup.
Why is it important?
Matched impressions show how well your campaign is hitting the mark. It’s one thing to serve ads, it’s another to serve them to the right person in the right format. This metric helps track that alignment.
7. Delivery discrepancy rate
What is it?
The difference between impression counts reported by different systems (e.g., ad server vs. DSP).
Why is it important?
Delivery discrepancy rate helps catch technical problems early. If your DSP says you served 1 million impressions but your ad server says 900k, you need to know why. Discrepancies can point to tagging issues, time zone mismatches, or worse - reporting errors.
Here's the formula:
Delivery discrepancy rate = ((System A - System B) ÷ Average of A and B) × 100
8. Impression share lost (ISL)
What is it?
The percentage of available impressions you missed due to budget or ranking limits.
Why is it important?
Impression share lost (ISL) is a visibility killer. It tells you how many chances you had to show your ad, but didn’t. If this number’s high, it’s usually a sign you need to increase your bid, improve your ad rank, or boost your budget.
Here's the formula:
Impression share lost = (Eligible Impressions − Impressions Delivered) ÷ Eligible Impressions × 100
9. Time-in-view rate
What is it?
The percentage of impressions that remained on screen for a minimum threshold of time.
Why is it important?
Time-in-view tells you if your ads are actually being seen long enough to register. This goes deeper than simple viewability and helps refine creative placement or duration strategies.
Here's the formula:
Time-in-view rate = (Impressions with qualifying view duration ÷ Total Impressions) × 100
10. Creative match rate
What is it?
The percentage of served impressions that used the intended (correct) creative variation.
Why is it important?
Creative match rate helps you verify that personalizations, language variants, or A/B tests are being executed as planned. A low rate might mean a trafficking error, a misconfigured ad set, or delivery defaults.
Here's the formula:
Creative match rate = (Correct Creative Impressions ÷ Total Impressions) × 100
Quick tips on reporting ad delivery metrics
When reporting on ad delivery, marketers can get more value and clarity by following a few essential best practices:
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Automate delivery checks:
Set up alerts and dashboards that monitor pacing, serving issues, or unusual drops in impressions or fill rate. This helps you act quickly instead of catching issues post-campaign. -
Segment by channel/platform
Analyze delivery by platform, placement, or environment (e.g., mobile vs. desktop, display vs. video) to pinpoint performance differences and tailor optimizations. -
Cross-check with billing
Reconcile vendor delivery reports with invoices to catch discrepancies in billing impressions or mismatched delivery windows. -
Track metrics over time
Look for trends in delivery metrics rather than just snapshots - this reveals seasonality, performance drift, or systemic issues. -
Contextualize anomalies
If something seems off (like a drop in matched impressions), check for campaign changes, creative swaps, or platform-side updates that might explain it. -
Report only what matters
Don’t overload reports with every available metric. Focus on the 3–5 delivery KPIs most relevant to campaign goals and stakeholders. -
Tie delivery to outcomes
Wherever possible, link delivery metrics to performance metrics (e.g., cost per net click, delivery vs. conversion rate) to provide strategic insight. Align internal reporting with what you’re invoiced for to catch discrepancies.
Conclusion
Ad delivery metrics aren’t just a technical formality; they’re your front line of truth. Tracking them effectively helps you verify campaign performance, uncover issues early, and ensure your media dollars are working as hard as they should.
Marketers who stay on top of ad delivery can improve efficiency, safeguard brand spend, and build more consistent results over time.
