Hello. It’s been a week since we spoke and it has been one long week, hasn’t it?

Some of you wrote to me with claims that you were wary of, things you had read or heard that you wanted fact-checked. That’s what I’m here for. But the sheer number of questions made me think that maybe it would be better to start by sharing some advice on how to verify statements yourselves.

To do this, I’ve written a step-by-step guide to fact-checking just one claim made by Donald Trump during Thursday’s press conference:

There are two Chicagos, as you know. One Chicago that is incredible, luxurious and safe. There is another Chicago that is worse than almost any of the places in the Middle East.

Step 1: Find out if Chicago really is segregated. (Heads up, do this now – it might be harder in the future. Two new Republican bills would stop government money from being used to collect data on racial segregation in the future.)

To do this, I’d do a Google image search for “racial segregation by US city” and then I’d research the origins of any map that looks relevant.

The most useful image result is University of Virginia’s “racial dot map”. Read the methodology which says “The map displays 308,745,538 dots, one for each person residing in the United States at the location they were counted during the 2010 Census. Each dot is color-coded by the individual’s race and ethnicity.”



Find Chicago and confirm that the city is indeed segregated (as are many others in the US).



Racial segregation in Chicago. Photograph: University of Virginia

Step 2: Ignore the word “incredible” (that is how my mom describes me when she is deliberately trying to avoid adjectives that can be verified) and find out if one part of Chicago is “luxurious and safe”.

Find crime maps (again, use a Google image search), but ignore crime maps that don’t take into account population (remember, people aren’t evenly distributed throughout a city, so those “crime hotspots” you’re looking at are probably just people hotspots).

Instead, find per capita crime maps. These ones take into account population size by dividing crimes by the total number of people living in a place. Discover that the homicide rate in Chicago does vary a lot by neighborhood but there’s no evidence of “two Chicagos”. It looks as though there are several.



Homicides in Chicago. Photograph: The Trace

Step 3: Set aside (momentarily) the fact that it makes no sense whatsoever to compare one US city to an entire region in the world. Also set aside racist undertones that Middle East is full of Arabs and therefore full of barbarians (and that white Chicago = good and black Chicago = bad).

We’ll still check Trump’s claim that Chicago is worse than most of the Middle East. Find data from the World Bank about the intentional homicide rate in each country. Make sure that you are making comparisons on the same scale (ie the data for Chicago is per 100,000 people, so the World Bank data should also be in the same units. It is.) Discover that as of 2014, there are 10 countries in the world where the intentional homicide rate is over 20 people per 100,000. None of these are countries in the Middle East.

Step 4: So it seems like Trump is right but that seems strange given the ongoing violence in Syria and Iraq. Check definitions to make sure there isn’t some other reason why countries in the Middle East aren’t at the top of the list. The World Bank counts intentional homicides as those “purposely inflicted as a result of domestic disputes, interpersonal violence, violent conflicts over land resources, intergang violence over turf or control, and predatory violence and killing by armed groups”. But the definition goes on that “killing in armed conflict is usually committed by fairly cohesive groups of up to several hundred members and is thus usually excluded”.

Realize this is why countries like Syria do not appear higher up on the list. Wonder why Trump is comparing homicides in a US city to international war zones.

Step 5: Get historical perspective. Find the most recent data and oldest data you possibly can to see how this has varied over time. Google “historic crime data Chicago”. A study from Yale which looks at crime in Chicago from 1965 to 2013 finds that Chicago is on track to have both the lowest violent crime rate since 1972, and lowest homicide rate since 1967 – but it turns out that study is not recent enough. Between 2015 and 2016, the number of murders increased by 59%, according to the study.

But whenever you hear about a percentage increase, find out what the number was before it increased (maybe there were 10 murders in 2015 and 16 murders in 2016 – that’s a 59% increase but it’s not so bad). It turns out though that there were 762 murders last year, according to the Chicago police department. That seems like a lot, but is it? See the final step ...

Step 6: Get context. Find out if Chicago has the highest murder rate in the country. Search for compiled police data which shows that it doesn’t – Chicago has the 12th highest homicide rate of any US city between 2011 and 2016 (the first three are Detroit, St Louis and New Orleans). Wonder why Trump is repeatedly calling out Chicago and not other cities.

Step 7: Remember that reality is complex. These 916 words don’t fully capture it (and Trump’s 32-word soundbite is further from the truth than Chicago is from the Middle East).



Would you like to see something fact-checked? Send me your questions! mona.chalabi@theguardian.com / @MonaChalabi