Professional development coaches from the Development Academy wing of Acuity Training compiled a list of the world's most eloquent leaders after reviewing more than 100 hours of footage from press conferences, speeches and other public addresses throughout 2020.
Ardern topped the list after being praised for her "emphatic leadership style".
"Jacinda Ardern employs an empathetic leadership style. She challenges the common perception that emotional communication shows weakness, instead choosing to approach the public with softer touch," the Development Academy wrote.
"She has a measured and authoritative sincerity about her – she is kind and compassionate, without shying away from tough issues."
Three of the leaders named in the top five are women, with German Chancellor Angela Merkel named as the second most eloquent leader, ahead of Indian Prime Minister Narendra Modi in third place and Canada's Justin Trudeau, who was ranked fourth.
Scotland's Prime Minister Nicola Sturgeon was ranked fifth, with praise for her response to the Covid-19 pandemic as well as her humour.
"Nicola Sturgeon has received a lot of praise for her response to the coronavirus pandemic – and it's not hard to see why.
"She is clear, calm and compassionate, he is not afraid to be tough or emotional, and she has a great sense of humour. There's no sense of performance with Sturgeon – she is very real."
Australian Prime Minister Scott Morrison came in at 10th place, with the Academy saying he "greatly improved his reputation since the country's devastating bushfires earlier this year".
"Morrison has been open, emotional and even vulnerable during his addresses to the Australian people, demonstrating to voters that he shares in their pain."
In stark contrast, US President Donald Trump and UK Prime Minister Boris Johnson were identified by the experts as two leaders whose presentation style needed improvement.
The experts said Trump has always taken a "thinking out loud approach" and "reacts to questions before he has given himself time to think and offer appropriate answers".
"He will often jump to a new topic before concluding the previous one, causing his audience to lose interest or become frustrated. His overuse of metaphors and analogies is confusing for many, and he occasionally slurs on words.
"Unlike Boris Johnson, who has made noticeable improvements since becoming Prime Minister, Trump has done little to address the flaws in his style of public speaking."
Experts described Johnson as a "unique public speaker" who has a tendency to "mutter or waffle" and his "use of odd or obscure references often left people confused about his message".
They did however praise Johnson for is recently improved communication and presentation skills.
Development Academy director Ben Richardson said: "World leaders have the ability to inspire us, motivate us, shock us and even scare us – there is tremendous power in great public speaking, and 2020 has certainly provided our heads of state with some serious talking points.
"But despite the requirement to make several public appearances and speeches in their roles, there are some world leaders who aren't always on the right track when it comes to addressing their nation.
"We decided to analyse the communication and presentation skills of leaders from around the world to determine the list and it's great to see so many female leaders featuring on it."
He added: "Jacinda Ardern for example, is a sincere and compassionate speaker, while Nicola Sturgeon is very engaging while demonstrating empathy."
"There are some fantastic – and not so fantastic – examples of public speakers from this research and it's fascinating that although there are only around 10% of women in leadership roles worldwide, female leaders make up 50% of the top communicators."
TOP 10
1. Jacinda Ardern, Prime Minister of New Zealand
2. Angela Merkel, Chancellor of Germany
3. Narendra Modi, Prime Minister of India
4. Justin Trudeau, Prime Minister of Canada
5. Nicola Sturgeon, First Minister of Scotland
6. Mette Frederiksen, Prime Minister of Denmark
7. Emmanuel Macron, President of France
8. Erna Solberg, Prime Minister of Norway
9. Giuseppe Conte, Prime Minister of Italy
10. Scott Morrison, Prime Minister of Australia
