Ad stacking fraud is a kind of impression fraud or click spam. Industry studies suggest that nearly 18–20% of digital ad impressions are affected by invalid or fraudulent traffic, meaning roughly 1 in 5 impressions delivers no real value.
It is one of the most common types of fraud that ails CPM and PPC campaigns, which is why proper fraud protection must be the top priority of any marketer.
When more than one ad is stacked on top of one another, in a single ad placement, this practice is known as ad stacking. It is a type of fraud and a notorious one at that.
The user is able to view only one ad, the one stacked on top, but as soon as they click on it, the impression registered goes to each ad in the stack. This leads to fake clicks and impressions that the advertisers have to pay for.
It is one of the most common forms of fraud in click-based campaigns and is known to drain resources, especially ad budgets, with no real results to show for.
The good news is that, although prevalent, ad stacking fraud is quite easy to detect. With the right guidance and information at hand, you can protect your affiliate marketing campaign from falling prey to this fraud.
How Does Ad Stacking Fraud Work?
There are numerous ways in which fraudsters execute ad stacking fraud:
A fraudster may place numerous ads at zero opacity into a single ad unit. In this way, the user is only able to see one ad while the rest of the ads placed behind it are invisible to them.
Sometimes, a fraudulent publisher may use banner rotation to load invisible ads, meaning that an invisible ad action will continuously keep happening behind a visible ad.
As soon as an impression is counted for an ad, it is replaced by another invisible ad, and the cycle continues. Even though a user is never able to actually see these ads, since they are able to trigger an impression by loading the required pixel, advertisers are charged for the impression and have to pay.
In other words, when multiple ads are stacked or layered over one another fraudulently to charge the advertiser falsely with no actual impressions, the practice is known as ad stacking fraud
Detecting Ad Stacking Fraud with Technical Means
Advertising fraud detection systems have evolved to incorporate technical signals and behavioral analysis to detect ad stacking fraud at scale. One of the primary means is through viewability measurement, which measures the likelihood that an ad will have the opportunity to be viewed by a user. If multiple ads deliver impressions on a user but only one is viewed, it is an indicator of both stacking and hidden layers.
A second primary method of detecting ad stacking fraud is by examining the DOM (Document Object Model) of the webpage to look for overlapping ad elements, zero opacity layers, or multiple ad tags being rendered in the same position. This allows for the ability to find instances where an ad is technically loaded but visually hidden.
Fraud detection tools will also commonly include traffic pattern analysis, which can identify a large volume of impressions from one placement/publisher, but have very low or no engagement, leading to raising flags to indicate that fraud may be present.
IVT (Invalid Traffic) filtering systems help to identify automated or manipulated impressions by assessing user behavior, device signals, IP frequency, and session anomalies. Also, some advanced systems employ machine learning models that are continually learning from historical fraud patterns to help identify new variations of ad stacking.
Why is it Important to Understand Ad Stacking Fraud?
Ad Stacking, like any other impression fraud, wastes marketers’ ad spend. Additionally, it creates issues with the campaign data.
Fake impressions result in poor ROAS as the budget allocated for your ads is drained and brings nothing in return.
Clicks and impressions from fraudulent ad stacking also have a negative effect on your campaign data, as a low conversion rate, even when impressions are high, may cause marketers to think that the creatives are not on par, even when that is not the case.
Protect Yourself From Ad Stacking Fraud
Organizations continually keep falling prey to ad stacking fraud, even though it is easy to detect and protect against. This is because it is one of the easiest ways to commit fraud, and most brands/marketers are not equipped with the right tools and guidance to protect themselves.
It is important to prioritize protection against fraud like ad stacking.
To make it easier for marketers, here is a list of ways that can help identify and protect yourself against ad stacking fraud:
- Keep a close check on campaign conversion rates. If you are observing low conversion rates yet high impressions, this can be an indication of ad stacking.
- If you are running more than one ad campaign, keep a check on the backend functions. This will allow you to identify if there are multiple clicks from a single device with the same timestamp.
- Keep up with the reports your platform vendor provides you with. Analyze the results of your campaign regularly.
- Make sure your platform offers top-of-the-line, best-in-industry anti-fraud solutions for your campaign and ads. This helps nip ad stacking in the bud. Anti-fraud tools detect fake traffic and clicks quickly. This helps you save your ad budget from going down the drain.
- Implementing an anti-fraud solution is a great idea since it helps curb the need for time-consuming manual traffic quality checks. An automated anti-fraud solution helps blacklist fraud device IDs, reveal fake user data, and therefore improves the overall performance of your campaign.
Best Practices to Follow to Prevent Ad Stacking Fraud
Affiliate managers and advertisers need to stay ahead of the curve when it comes to advertising best practices.
Since the affiliate marketing industry is evolving quickly, ad stacking fraud is becoming more prevalent with each passing day, and this is turning out to be a major issue for marketers.
While ad stacking might seem like a quick way to increase your revenue, it can harm the reputation of your business, as stacking multiple ads in a single ad space is a fraudulent practice.
To ensure that your affiliate marketing campaign succeeds in the long run with no repercussions, make sure that your business follows industry best practices and does not indulge in fraudulent activities.
One of the thumb rules that any affiliate marketer or advertiser must follow, while running ads, is to prioritize quality over quantity.
When it comes to ad placements, strategically place high-quality ads on your website. This approach ensures that your ads bring in meaningful clicks and conversions.
Transparency, for any organization, is the key to maintaining a positive reputation in the industry.
By being open with your affiliates about the number of ads and their placement, you save yourself from accidental stacking.
Since affiliates are in the loop, they will refrain from placing ads on the same sites, which in turn will safeguard you against stacking.
FAQs
1. How does an anti-fraud platform help prevent ad stacking fraud?
An anti-fraud platform continuously analyzes traffic patterns, detects suspicious publisher behavior, identifies invalid impressions, and flags abnormal click activity in real time. It enables advertisers to block fraudulent traffic, protect campaign budgets, improve reporting accuracy, and focus their spend on genuine users who are more likely to convert.
2. Why is viewability important in preventing ad stacking fraud?
Viewability measures whether an ad had a genuine opportunity to be seen by a user. Since stacked ads remain hidden behind visible ads, they typically fail viewability standards. Monitoring viewability metrics helps advertisers identify suspicious inventory and reduce spending on placements that generate fake impressions.
3. Can ad stacking fraud harm publishers as well as advertisers?
Yes. Publishers that intentionally engage in ad stacking risk losing partnerships, damaging their reputation, and being removed from advertising networks. Even legitimate publishers can suffer if fraudulent inventory enters their ecosystem, making transparency and compliance with industry standards essential for maintaining advertiser trust.
4. Which types of advertising campaigns are most affected by ad stacking fraud?
Ad stacking primarily affects display advertising campaigns, especially those using CPM and PPC pricing models. Programmatic advertising, affiliate marketing, and mobile app advertising campaigns are also vulnerable because fraudsters can generate fake impressions without providing any real visibility to users.
5. How can advertisers identify ad stacking fraud?
Advertisers can identify ad stacking by monitoring unusually deep impressions with very low click-through or conversion rates. Reviewing publisher performance, analyzing traffic quality, checking for suspicious device activity, and using an ad fraud detection platform can help uncover hidden ad placements and invalid impressions before they impact campaign performance.
