The creator of Numbeo had a good idea making that website but I can tell most of the information about crimes rates are not accurate, basically anybody can rate any city however they want and for personal interests it ends up being fake.
For example, a few touristic companies from my hometown Romania have been rating cities like Bucharest, Craiova or Constanza as very safe and safer than cities in Western Europe just to gain tourism, and after talking to some of them tourists I met online almost half of them tell me that they have been mugged in Bucharest or Constanza, some of them told me they didn't expect such thing (since they checked Numbeo first). Look, I've been in Bucharest and it's not a very dangerous city and it's probably safer than Paris or London, but come on, "problems such as armed assault: VERY LOW?" are you kidding me? Or crime in Craiova or Constanza or Ploiești low? This is just not accurate and very bad for our tourists since they will get very disgusted when they see the reality, I love my country and I wish those datas where true, but i'm more realistic than anything.

And this is not only unaccurate in Romania, it's most of the countries, according to Numbeo, Belarus is the most dangerous country in Europe? Really? Belarus? There's even anything worthy you can rob there? And more lies like for example Coventry and Bradford being more dangerous than Birmingham and Manchester, or Italy being safer than the UK or Sweden, or Valencia being one of the safest cities in the world, I have been mugged and assaulted countless times in Eastern Valencia in only 2 years and other friends got robbed multiple times as well so no, the crime rate in Valencia is not "very low" which is what Numbeo indicates.

I have also lived during 6 months in Casablanca and Tangier, Morocco and I have felt much safer than in Spain or my home country even though I didn't speak the local language and neither knew nobody, still according to Numbeo, cities like Barcelona or Malaga are safer than Casablanca, it's just impossible.

The only continent where the data is mostly accurate is South America which is where I traveled for the last 3 years, Venezuela and Argentina seemed for me the most dangerous by far, especially Caracas and Rosario, other countries like Colombia, Uruguay or Ecuador where very nice and I didn't have a problem not even in big cities like Guayaquil or Bogotá.
But hey, great job, it could be a very helpful website but in fact it ended up being the opposite, hope my review helped you guys, I feel very bad for the tourists or the statesmen who get wrong information from here.
Keep travelling and have a great day