20 safest cities in the world, 2015

The world is increasingly urban, a trend that's expected to continue for decades. In the United States, at least 80 percent of the population lives in a city or suburb.

Those concentrations of people create economies of scale but also risks, like violent crime, contagious diseases, even digital network vulnerabilities.

The Economist Intelligence Unit ranked the 50 cities listed above for overall safety, using an index of indicators in four categories. (The 50 indexed cities were chosen partly for how representative they were of their region and partly for whether data points were accessible.) All five of the U.S. cities on the list showed up in the top 20, but only one — New York — appeared in the top 10.

The four categories:

Personal safety. The most obvious category, this one takes into account illegal activity, police engagement and the prevalence of violent crime. No U.S. city shows up in the top 10 worldwide, though Toronto does, at No. 7. Singapore is No. 1. Of the five U.S. cities in the index, Washington ranks highest at No. 17, followed by San Francisco at 21, Los Angeles at 23, Chicago at 25 and New York at 28.

Health security. Data that went into this measurement included the ratio of hospitals to population size and residents' life expectancy. Surprisingly, New York comes in at No. 2 — the only North American city to show up in this category's top 10, which is dominated by European cities. Zurich is No. 1.

Infrastructure safety. This category measures factors including road quality, car accidents and pedestrian deaths per year, deaths from natural disasters, and the percentage of the population living in urban slums. The only U.S. city in the top 10, San Francisco, just barely makes it there, tying with Abu Dhabi for No. 10.

Digital security. Here, the United States has its best showing, with four out of its five indexed cities appearing in the top 10. (Alarmingly, it's the nation's capital that does not have a strong enough score.) The presence of cyber security teams contributes to a higher score in this category, while a high frequency of identity theft and large amounts of money lost to online crime are a couple of the factors that drive a score down. New York (3) and L.A. (6) both beat out San Francisco in this category, possibly because the tech hub's extensive reliance on digital technology also creates vulnerabilities.

These are the 20 safest cities:

20. FRANKFURT, GERMANY

Safest Cities Index score: 73.05 out of 100 (with 100 the best possible)
Personal safety ranking: 16 out of 50 cities
Health security ranking: 4 out of 50 cities
Infrastructure safety ranking: 20 out of 50 cities
Digital security ranking: 33 out of 50 cities
Life expectancy: 79

19. WASHINGTON, D.C.

Safest Cities Index score: 73.37 out of 100 (with 100 the best possible)
Personal safety ranking: 17 out of 50 cities
Health security ranking: 19 out of 50 cities
Infrastructure safety ranking: 29 out of 50 cities
Digital security ranking: 15 out of 50 cities
Life expectancy: 76

18. LONDON

Safest Cities Index score: 73.83 out of 100 (with 100 the best possible)
Personal safety ranking: 12 out of 50 cities
Health security ranking: 22 out of 50 cities
Infrastructure safety ranking: 25 out of 50 cities
Digital security ranking: 16 out of 50 cities
Life expectancy: 82

17. LOS ANGELES

Safest Cities Index score: 74.24 out of 100 (with 100 the best possible)
Personal safety ranking: 23 out of 50 cities
Health security ranking: 26 out of 50
cities
Infrastructure safety ranking: 19 out of 50 cities
Digital security ranking: 6 out of 50 cities
Life expectancy: 80

16. CHICAGO

Safest Cities Index score: 74.89 out of 100 (with 100 the best possible)
Personal safety ranking: 25 out of 50 cities
Health security ranking: 23 out of 50 cities
Infrastructure safety ranking: 13 out of 50 cities
Digital security ranking: 10 out of 50 cities
Life expectancy: 78

15. BARCELONA, SPAIN

Safest Cities Index score: 75.16 out of 100 (with 100 the best possible)
Personal safety ranking: 11 out of 50 cities
Health security ranking: 7 out of 50 cities
Infrastructure safety ranking: 14 out of 50 cities
Digital security ranking: 29 out of 50 cities
Life expectancy: 82

14. MONTREAL, CANADA

Safest Cities Index score: 75.6 out of 100 (with 100 the best possible)
Personal safety ranking: 29 out of 50 cities
Health security ranking: 20 out of 50 cities
Infrastructure safety ranking: 6 out of 50 cities
Digital security ranking: 11 out of 50 cities (tied with Toronto)
Life expectancy: 81

13. TAIPEI, TAIWAN

Safest Cities Index score: 76.51 out of 100 (with 100 the best possible)
Personal safety ranking: 5 out of 50
cities
Health security ranking: 9 out of 50 cities
Infrastructure safety ranking: 22 out of 50 cities
Digital security ranking: 21 out of 50 cities
Life expectancy: 83

12. SAN FRANCISCO

Safest Cities Index score: 76.63 out of 100 (with 100 the best possible)
Personal safety ranking: 21 out of 50 cities
Health security ranking: 16 out of 50 cities
Infrastructure safety ranking: 10 out of 50 cities (tied with Abu Dhabi)
Digital security ranking: 8 out of 50 cities
Life expectancy: 80

11. HONG KONG

Safest Cities Index score: 77.24 out of 100 (with 100 the best possible)
Personal safety ranking: 6 out of 50
cities
Health security ranking: 15 out of 50
cities
Infrastructure safety ranking: 40 out of 50 cities
Digital security ranking: 4 out of 50
cities
Life expectancy: 84

10. NEW YORK CITY

Safest Cities Index score: 78.08 out of 100 (with 100 the best possible)
Personal safety ranking: 28 out of 50 cities
Health security ranking: 2 out of 50 cities
Infrastructure safety ranking: 16 out of 50 cities
Digital security ranking: 3 out of 50 cities
Life expectancy: 81

9. MELBOURNE, AUSTRALIA

Safest Cities Index score: 78.67 out of 100 (with 100 the best possible)
Personal safety ranking: 8 out of 50 cities
Health security ranking: 14 out of 50 cities
Infrastructure safety ranking: 2 out of 50 cities
Digital security ranking: 20 out of 50 cities
Life expectancy: 86

8. TORONTO, CANADA

Safest Cities Index score: 78.81 out of 100 (with 100 the best possible)
Personal safety ranking: 7 out of 50
cities
Health security ranking: 21 out of 50 cities
Infrastructure safety ranking: 8 out of 50 cities
Digital security ranking: 11 out of 50 cities (tied with Montreal)
Life expectancy: 81

7. ZURICH, SWITZERLAND

Safest Cities Index score: 78.84 out of 100 (with 100 the best possible)
Personal safety ranking: 13 out of 50 cities
Health security ranking: 1 out of 50 cities
Infrastructure safety ranking: 1 out of 50 cities
Digital security ranking: 19 out of 50 cities
Life expectancy: 84

6. SYDNEY, AUSTRALIA

Safest Cities Index score: 78.91 out of 100 (with 100 the best possible)
Personal safety ranking: 10 out of 50 cities
Health security ranking: 17 out of 50 cities
Infrastructure safety ranking: 3 out of 50 cities
Digital security ranking: 14 out of 50 cities
Life expectancy: 81

5. AMSTERDAM, THE NETHERLANDS

Safest Cities Index score: 79.19 out of 100 (with 100 the best possible)
Personal safety ranking: 9 out of 50
cities
Health security ranking: 13 out of 50
cities
Infrastructure safety ranking: 4 out of 50 cities
Digital security ranking: 17 out of 50 cities
Life expectancy: 82

4. STOCKHOLM, SWEDEN

Safest Cities Index score: 80.02 out of 100 (with 100 the best possible)
Personal safety ranking: 4 out of 50
cities
Health security ranking: 10 out of 50 cities
Infrastructure safety ranking: 21 out of 50 cities
Digital security ranking: 7 out of 50 cities
Life expectancy: 82

3. OSAKA, JAPAN

Safest Cities Index score: 82.36 out of 100 (with 100 the best possible)
Personal safety ranking: 2 out of 50
cities
Health security ranking: 6 out of 50 cities
Infrastructure safety ranking: 12 out of 50 cities
Digital security ranking: 5 out of 50 cities
Life expectancy: 83

2. SINGAPORE

Safest Cities Index score: 84.61 out of 100 (with 100 the best possible)
Personal safety ranking: 1 out of 50
cities
Health security ranking: 12 out of 50
cities
Infrastructure safety ranking: 7 out of 50 cities
Digital security ranking: 2 out of 50
cities
Life expectancy: 82

1. TOKYO

Safest Cities Index score: 85.63 out of 100 (with 100 the best possible)
Personal safety ranking: 3 out of 50 cities
Health security ranking: 8 out of 50 cities
Infrastructure safety ranking: 5 out of 50 cities
Digital security ranking: 1 out of 50 cities
Life expectancy: 82

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