Taking the Met's figures and assuming that sex crimes are committed by males age 15-39...
According to Nomis, there is 1,767,660 men aged 15-39 in London. Assuming 0.27% were born on 2 January, that's roughly 4,770 people. With 34 arrests between them, that's an arrest rate of 0.7%.
According to Asylum stats, there are 12,140 asylum seekers on support in London. Assuming half of these are undocumented (and thus would have 1 January as their recorded birth date) and pretty much all undocumented are men, that's 6,070 people. With an excess of 121 arrests of 1 January shared between them, that's an arrest rate of ~2%, roughly 2.8x the rate above.
Assuming asylum seekers are much more likely to not be known to the victim (a fair assumption, if you read the news stories), then the disparity for certain categories of crime would probably be much larger.
Though, stranger offences more often lead to an arrest, apparently.
When you have gone to the trouble of doing it by date of birth you should really age adjust the analysis. Immigrants are nearly always very young. Most violent crime - by any ethnicity - is done by young people in their early 20s. That really should be the comparison.
But doesn't 1st January being the assigned default mean there's many more people in total with 1st January as their birth date?
So this could well just be a population size difference? Surely you would need to know the number of people currently living in the country with recorded birthdays on the 1st vs other days to see if the rate of offences is different? Your live births stats don't work because no one migrating into the country will be in them.
I may be wrong but I think sexual offences are almost always committed by males who are post-puberty, and I guess mostly by young men. Asylum seekers tend to be young men.
Taking the Met's figures and assuming that sex crimes are committed by males age 15-39...
According to Nomis, there is 1,767,660 men aged 15-39 in London. Assuming 0.27% were born on 2 January, that's roughly 4,770 people. With 34 arrests between them, that's an arrest rate of 0.7%.
According to Asylum stats, there are 12,140 asylum seekers on support in London. Assuming half of these are undocumented (and thus would have 1 January as their recorded birth date) and pretty much all undocumented are men, that's 6,070 people. With an excess of 121 arrests of 1 January shared between them, that's an arrest rate of ~2%, roughly 2.8x the rate above.
According to Crime Survey for England and Wales, only ~15% of rapes or sex assaults by penetration are committed by a stranger (https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/articles/natureofsexualassaultbyrapeorpenetrationenglandandwales/yearendingmarch2025/pdf).
Assuming asylum seekers are much more likely to not be known to the victim (a fair assumption, if you read the news stories), then the disparity for certain categories of crime would probably be much larger.
Though, stranger offences more often lead to an arrest, apparently.
When you have gone to the trouble of doing it by date of birth you should really age adjust the analysis. Immigrants are nearly always very young. Most violent crime - by any ethnicity - is done by young people in their early 20s. That really should be the comparison.
Once we eventually make the Home Office publish the data all kinds of analysis will be possible!
But doesn't 1st January being the assigned default mean there's many more people in total with 1st January as their birth date?
So this could well just be a population size difference? Surely you would need to know the number of people currently living in the country with recorded birthdays on the 1st vs other days to see if the rate of offences is different? Your live births stats don't work because no one migrating into the country will be in them.
What happens if you control for age?
I may be wrong but I think sexual offences are almost always committed by males who are post-puberty, and I guess mostly by young men. Asylum seekers tend to be young men.
Could this explain, or part-explain, the finding?
All racehorses born in the northern hemisphere have 1 January as the date of birth, in the southern hemisphere it is 1 August.
Ingenious piece of analysis!
Fascinating piece of work