articles published since 2011 on "grooming gangs" (there were none before that apparently)
That's a clue there's something wrong with his picture, because on this thread we've seen an article from 2004 about child sexual abuse by a gang of ethnically Asian men in Bradford.
Goodwin shows his working, and instead of searching for separate words "groom* " AND "gang" he has searched for a particular phrase: "grooming gang".
It's a common phrase, but using it as a search term doesn't catch the 2004 article – and doesn't even seem to catch Andrew Norfolk's seminal 2011 article which Goodwin is enthusing about. That says "grooming by gangs".
(Someone with a Times subscription might be able to check the whole article; I've only seen a poor image of the front page. "Scandal of the 1,400 Lost Girls", Times, 27 Aug 2014.)
I've now looked, and neither of the 2013 Guardian articles linked above on this thread contains the phrase "grooming gang"; Goodwin won't have found them.
Instead they say "child sex abuse ring" and "gang of abusers [...] child sexual exploitation" (in line with what posters say they find more useful).
Eg
"The woman spoke out as a jury at the Old Bailey convicted seven men responsible for running an underworld child sex abuse ring in the Cowley area of Oxford of 43 charges of rape, child prostitution, trafficking and procuring a backstreet abortion. Six victims gave harrowing evidence during the three-and-a-half month trial, but police believe the number of girls recruited by the gang and abused numbers more than 50."
https://www.theguardian.com/society/2013/may/14/oxford-abuse-ring-social-services
A gang of abusers who subjected vulnerable girls in Oxford to years of rape, torture and extreme sexual violence has been convicted at the Old Bailey in one of the biggest child sexual exploitation trials in recent years.
https://www.theguardian.com/uk/2013/may/14/oxford-gang-guilty-grooming-girls
Unfortunately I don't have access to Lexis, the nice database Goodwin used, so I can't repeat his exercise with better search terms.