This Report Says Ad Blockers Cut Publishers’ Mobile Load Times in Half

But don't really affect big brands' websites

There's been plenty of hand-wringing in the media industry over the past year about mobile ad blocking and apps that wipe out all of the ads that pop up on websites. Consumers say they download such apps to avoid annoying ads that make it difficult to access content on publishers' sites. Publishers are willing to experiment with those types of ads because they're a revenue source.

Today, website performance company Catchpoint Systems is releasing a report that puts at least part of the ad-blocking debate in perspective: Publishers' sites are loaded with heavy ads that slow down load times, and ad blockers do indeed improve load times significantly.

From May 1 to May 31, Catchpoint Systems analyzed the speeds of 20 mobile sites representing five publishers and 15 brands. Each site was tested for 15 minutes at a time—with ad blockers turned on and then off—and its average load time measured. It's important to note that three of the companies analyzed—Best Buy, Forbes and The Huffington Post—are clients of Catchpoint Systems, although the results don't necessarily paint a great picture for any of them.

It's also important to note that Catchpoint Systems' research only includes data collected from Pi-Hole blockers, a network-level technology built into ad blockers that strips out all ads served on a website, meaning that the results may be different for other types of ad blockers that use techniques like whitelisting to only block certain types of ads

Publishers that stuff their sites with ad units requiring lots of data like video or formats that use large file sizes suffer the most, per Catchpoint's assessment. The five publishers' sites the company measured were The Huffington Post, Forbes, Fox News, The New York Times and CNN.

"Mobile news site visitors may be more prone to engage ad blockers due to the bloated nature of mobile news pages," the report reads.

CNN had the slowest website, taking an average of 14.8 seconds to load a page. With an ad blocker turned on, the average load time was 7.6 seconds, a roughly 51.4 percent increase in speed.

The New York Times' load speeds jumped approximately 55 percent from 8.8 seconds without an ad blocker to 4.8 seconds with one.

On Fox News, the average page took 8.3 seconds to load, which improved to 5.8 seconds when a blocker was turned on. And Forbes' load speed increased 1.6 seconds (5.8 to 4.2) by turning on a blocker.

The Huffington Post is the only publisher with speeds that actually decreased when an ad blocker was turned on. Pages loaded in 3.5 seconds when the ad blocker was off and slowed to 4.4 seconds with it on, indicating the blocker had to work harder to load data-heavy editorial content.

Across all five publishers, Catchpoint said web performance increased an average of 27 percent to 49 percent with ad-blocking software.

In terms of other industries, retail and travel brands also saw improvements in speed when ad blockers were on. Ad blocking had the biggest impact on Target—its load time decreased from 9.3 seconds to 8.2 seconds with a blocker. Costco's site clocked in at an impressive 1.6 seconds with a blocker, down from 2.5 seconds without one.

As a category, travel sites reported improved speeds between 19 percent and 51 percent with ad blockers.

Conversely, websites for financial service sites—including Bank of America, Chase, Citibank and Wells Fargo—loaded significantly slower when ad blockers turned on. Interestingly, such sites don't typically serve a lot of ads, meaning ad blockers required more time to load pieces of content like login and authentication information.

"While our findings show that advertising-dependent sites tend to load much faster with ad blocking engaged, there was a surprising number of sites where user experience actually got worse," Mehdi Daoudi, CEO and co-founder of Catchpoint Systems, said in the report. "The bottom line: You can no longer assume a mobile site will always load faster with ad blocking on."

A handful of brands—Amazon, Booking.com and Capital One—didn't notice much of a difference in load times with or without blockers. Amazon in particular has a lightning-fast site that loaded in 1.64 seconds without an ad blocker and 1.68 seconds with one on.

Meanwhile, a separate report Tuesday from eMarketer claims 69.8 million Americans will turn on an ad blocker this year. That would represent a 34.4 percent jump from the 51.9 million people who did so in 2015. Next year, the number will hit 86.6 million internet users in America, according to the eMarketer report.

Take a look at the results for all 20 brands in Catchpoint Systems' research below.