Hosts France are flying high in the medal table this year, having not finished in the top five overall since 1948.

The teams above them in the top four are regular table-toppers China and the USA, and – after the latest flurry of medals – Team GB are not far behind.

Previous hosts Japan sit a couple of places below Team GB at the time of writing, having finished third at the Tokyo games.

In fact, five of the current top six have hosted the Olympics this century and the only ones that haven’t (USA) are hosting next time.

Part of that is to do with finances. Hosting the Olympics is expensive, and countries that can afford to host them also tend to be able to afford better facilities, coaching, equipment and otherwise support athletic development and elite performance.

But how much of a boost is it having a home crowd behind you, and does it leave a legacy of success?

It’s pretty significant, according to the data.

Looking at all of the hosts since 2000 – Australia, Greece, China, Great Britain, Brazil and Japan – countries won almost three times as many medals in their host year on average compared with their tally three Olympics before.

Why it was so tough for Greece

Greece is the most extreme example. They won 16 medals in their host games in 2004, as many as they did in the six Olympics from 1976 to 1996 added together. In the four Games since then (not including the current one) they won 15.

Dr Matthew Robinson, professor of sport management at the University of Delaware, leads an IOC-affiliated programme that funds sports development around the world, and has written a book chapter titled The Impact Of The Olympics On The High Performance Legacy Of A Host Country.

He says Greece’s sporting legacy post-Athens 2004 failed because they lacked some of the crucial economic factors typically required to host the Olympics.

“Once the Games were over, [Greek] sport had nothing. They were actually harmed in hosting the Games, from a sporting perspective,” he says.

Dr Robinson said there have been criticisms of poor planning that led to the non-use of facilities after the Games, but also that the post-2008 economic crisis which engulfed Greece should be taken into consideration.

A considerably smaller economy than the likes of China, the UK, France or Japan, Greece spent $11bn on hosting the Olympics in 2004, equivalent to almost 5% of its annual GDP. That’s more than most countries allocate towards their militaries each year.

China spent $42bn on the 2008 Olympics, but that equated to less than 1% of their annual economic production, five times less than Greece as a proportion.

The UK – perhaps benefitting from existing sporting and transport infrastructure – spent a comparatively paltry $4bn on London 2012, 0.16% of GDP at the time.

On that measure, the financial burden on Greece hosting the Olympics was 30 times greater than it was on Britain.

Medal improvements before the host Games

Most other countries have sustained medal success after hosting, although mostly not quite at the same levels as when they had the home fans behind them.

But interestingly, the data also shows that there tends to be gradual improvements in medals won at the Olympics prior to the hosting year, even if most countries eventually peak when they are hosting.

Looking at the other countries that reached the final stage of the bidding process for the 2012 Olympics (awarded in 2005), medal success was fairly flat for France, Russia, Spain and the US.

But for Team GB it rose by 70% from 2004 to 2008, and by another 43% from 2008 to 2012, meaning the tally was almost 2.5x higher overall in 2012 compared with 2004.

“In the lead up to hosting, you’ll see governments get behind sport in that country. Building out infrastructure, more facilities, more focus, more attention,” Dr Robinson explains.

“A lot of countries will put strategic plans into development or incentives for particular sports to excel in the lead up to the Games. And then you’ll see there’s a slight improvement in the Olympics before you host.

“You put in almost eight years of investment in enhancing sports and you’ll see results.”

How Team GB and Brazil built success after hosting

Hosting itself also brings advantages, according to Dr Robinson.

He says: “When you host you factor in the home-field advantage, where athletes are not travelling, going to a different time-zone, and the psychological lift associated with being the home-team athlete.”

Brazil and Team GB seem to have built on this investment best, improving upon medal-winning success even after their host years.

Brazil won more at Tokyo in 2021 than they did in Rio in 2016, and Team GB have managed to sustain their medal success from 2012 to levels far above what we were used to.

From 1948 to 2004 Team GB secured 21 medals per Olympics on average. Since 2012 they’ve averaged three times as many.

Dr Robinson says the legacy effect of the UK Games on sport in Britain has been impressive.

“People talk about the benefits of the Games, and it’s always from an economic impact perspective – infrastructure has been built, there are cultural benefits too, in terms of tourism and investment etc.

“London did an amazing Games. They had an incredible legacy plan in place that meant the facilities are still used. Athletes benefited from it before, during, and after the Games.

“London is a model example of how the country has benefited from being a host, and sport being one of the things that has benefited, because I think often sport is discounted.”

Dr Matthew Robinson wrote The Impact Of The Olympics On The High Performance Legacy Of A Host Country, a chapter in Handbook Of Sport And Legacy: Meeting The Challenge Of Major Sports Events, by R Holt and D Ruta.

The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling, we aim to better explain the world while also showing how our journalism is done.