Snapchat may be one of the hottest social networks, but unlike rivals Twitter and Facebook, it can be a bit tougher to measure the success of any individual or organization on the platform.

Still, Burson-Marsteller, a global public relations and communications firm, decided to take a stab at it. The firm regularly issues reports on how world leaders and governments are using Twitter and Facebook. Now, it has decided to take a look at Snapchat.

“Snapchat is the fastest growing social media platform and, according to the latest statistics, almost two thirds of its users are aged between 13 and 24 years old, making it the ultimate platform to reach young audiences,” says the Burson-Marsteller report. “It therefore comes as no surprise that government leaders are starting to set up accounts on the platform to reach out to future leaders.”

What makes tracking Snapchat tricky is that, unlike other social networks, it doesn’t make the number of followers an account has public, nor the views a snap gets. And snaps disappear after 24 hours.

Not surprisingly, in this initial review, the number of users is quite small: just 16 heads of state and international organizations. Those ranks include four presidents, three governments, two foreign ministries, and a foreign minister:

The list includes:

“Despite its limitations some governments have discovered Snapchat to be a formidable broadcasting tool to target a decidedly younger audience, either by chronicling the public activities of their leaders or to raise the level of public engagement at selected events,” says the report. “International organizations, particularly UNICEF and the European Parliament, use Snapchat to engage with their followers, often reposting their snaps. And the numbers are impressive: the UK Foreign Office reports an engagement rate of more than 60% (Snap views in comparison to followers) and a 90% completion rate (last snap views minus first snap views) of its stories.”

According to the report, the UKForeignOffice was the first of this group to create a Snapchat account, which it opened last September in conjunction with the Rugby World Cup.

The U.S. State Department followed suit in December for the COP21 environmental summit in Paris. The WhiteHouse jumped on the bandwagon in January.

The report highlights UNICEF and the European Parliament as probably doing the best job on Snapchat. The European Parliament shares its agenda and engages with followers on the platform. UNICEF has used Snapchat to tell powerful stories about relief work being done in places like Yemen.

Finally, the reports offers some critical advice to governments that are considering embracing Snapchat. Most notably: “Don’t vomit rainbows, that’s what mean kids do.”