The Holmes Report and ICCO are seeking input into the 2014 World PR Report, which ranks the world's biggest PR agencies and identifies key global industry trends and issues.

The information gathered in this survey will be used to compile the annual list of the 250 largest PR firms in the world, which serves as the basis for an estimate of the size and growth of the public relations industry globally.

It will also form the basis of the World PR Report 2014, produced in collaboration with ICCO. A new section in the report, sponsored by Capstone Hill, will look at how the industry can overcome the specific talent challenges it is facing.

Last year's Report found a PR agency industry that is growing at around 8% per year, to approximately $11bn in fee income, employing at least 75,000 people.

Despite this growth, though, the study found that plenty of challenges persisted. PR agency leaders pointed to economic conditions as their biggest concern, alongside talent and new technologies. Meanwhile, overall industry optimism dipped slightly, despite obvious industry growth in both mature and emerging markets.

"The world PR report is a truly unique study, and last year's edition received overwhelmingly positive response from ICCO members and the global PR industry," said ICCO executive director Francis Ingham. "We are delighted that our partnership with the Holmes Report allows us to produce such valuable industry research."