SAN FRANCISCSO: The top five mobile network operators in the world are all from France and the UK, leaving their US competitors in their wake, according to new analysis of customers' app experience.

For its Mobile Network Experience Index, research firm STL Partners and Apteligent, an app analytics firm, evaluated customer app experience on 27 mobile networks across seven countries – the US, France, the UK, Italy, Spain, Germany and Canada.

The study measured four key components of a user's experience, such as download speed, error rate, average latency and latency consistency (the percentage of app requests that take longer than 500ms to complete).

Bouygues Telecom of France scored highest on the index after recording consistently high results across all four measures to reach a total index reading of 76 out of 100.

It was followed closely by two other French operators – Free (73) and Orange(70), which scored highly despite being let down by the number of app errors experienced by its users.

The top five was rounded out by two British operators, EE (65) and O2 (61), which scored well on most measures except download speeds. Another UK operator, 3, was ranked sixth with an index score of 58.

The five worst operators identified in the report were E-Plus of Germany (26), Wind of Italy (26), Telefónica's Movistar of Spain (33), Sprint of the US (33), which scored poorly on error rate and download speed, and 3 Italy (36).

Surprisingly, given the extensive 4G network available in the US, the country's mobile networks performed poorly.

T-Mobile, the best-performing US operator, scored only 45 – a full 41 points below Bouygues Telecom – while Verizon and AT&T, the US market leaders, scored just 43 and 37 respectively. All US operators performed very poorly on error rate, the report said.

Chris Barraclough, Partner at STL Partners and lead author of the report, said the index showed in simple terms which operators were likely to do the best job for users.

"A lot of people spend more time using apps than anything else on their phones, but how can they compare what they get today with what they really could be getting?" he asked.

Andrew Levy, CSO at Apteligent, echoed his remarks. He said: "This report is another form of analysis to help our clients improve, which is especially prudent as customers' understanding of the operator's role in performance continues to grow, and they begin to consider these factors when choosing a mobile service provider."

Data sourced from STL Partners, Apteligent; additional content from Warc staff