A new report has found gaps in the ad libraries of the world’s largest social media platforms, hindering basic transparency efforts ahead of a historic global election year.

The audit, published by the nonprofit Mozilla Foundation and the Finnish disinformation research company CheckFirst, found significant shortcomings in the ad libraries of Meta, TikTok, and LinkedIn, as well as major failings in the ad libraries of Alphabet and X (formerly Twitter).

Content from ad libraries has regularly been the foundation for investigations into pharmaceutical companies, e-commerce giants, right-wing influencers, presidential election campaigns, and foreign election interference. In particular, these libraries are an important tool for reporters looking to identify disinformation, paid influence campaigns, or the provenance of viral posts. They’re also vital for reporters who are tracking political messaging and voter targeting leading up to an election day.

In 2024, more than 60 countries will hold major elections and over half of the world’s population will be eligible to go to the polls. These ad libraries will be under immense pressure in the coming months, and the researchers claim most may not be up to the challenge.

“Ad transparency tools are essential for platform accountability — a first line of defense, like smoke detectors. But our research shows most of the world’s largest platforms are not offering up functionally useful ad repositories,” said Mozilla’s EU advocacy lead Claire Pershan in a release for the report. “The current batch of tools exist, yes — but in some cases, that’s about all that can be said about them.”

X, most notably, has no web interface. The ad library only provides slow-loading CSV files that create a huge amount of friction for any journalist trying to track or report on ads circulating on the platform at any scale. One CSV file often takes between five to ten minutes to load. Most basic ad library searches on other platforms take just seconds.

Once downloaded, there are no built-in filtering options, requiring journalists to convert the file to properly narrow the data. The content itself is not visible, showing URLs to the post instead. X also provides no help lines, tips, guidelines, or feedback — which puts up even more barriers to entry.

“X’s transparency tools are an utter disappointment,” said Pershan, echoing the report’s call for the company to build a proper ad library portal and better user experience.

Alphabet marked slightly higher in the audit, earning the grade of “bare minimum data and functionality.” The company currently operates a joint ad library for both YouTube and Google search, but has no keyword search option and does not allow you to filter the posts by platform. Users can only search by domain and advertiser name, making it harder to conduct even basic searches.

For YouTube, researchers could find 100% of the ads they identified in the library. But for Google Search that number dropped down to 67%, meaning a significant portion of ads were missing altogether.

Across the board, many of the ad libraries distinguished between advertising content and commercial “influencer” or “branded” content. Influencer posts in some cases are housed in a different library, but many platforms simply don’t collect information on branded posts at all. Years of research by election watchdog groups has shown that influencer posts and “sponcon” are often an important part of election disinformation and interference campaigns.

The report calls for platforms to collect more of these influencer posts, and roll out better tools to search through them.

The Digital Services Act (DSA), a European Union (EU) law that took effect last August, required major platforms to create a public and searchable ad repository. With EU’s June parliamentary election around the corner, the rollout and expansion of these libraries could not be more timely.

The report does credit some major platforms for increased transparency since the DSA was passed — in particular improvements at TikTok, Meta, and LinkedIn. Still, no platform received a full passing grade in the audit.

For example, Meta now has searchable historical data, going back six years, and filtering options to refine and narrow searches. The platforms still received significant knocks on performance. On Facebook, the researchers could only find 65% of the ads they identified in the library, showing again that ads were slipping through the cracks.

On TikTok, those figures were slightly higher, with 85% of ads identified on the For You Page, appearing in the ad library.

“Who pays for ads and how they’re targeted is crucial in helping watchdogs look out for the public interest — whether that’s fair elections, public health, or social justice,” said Amaury Lesplingart, chief technology officer and co-founder of CheckFirst. “In short, if you see an ad telling you that climate change is a hoax, you might be interested to know if that ad’s paid for by the fossil fuel industry.”