Following quoted from here.
You'll remember Cameron's comment about 120,000 families from hell who ruin life for the rest of us. Where did that figure come from? Jonathan Portes from www.niesr.ac.uk decided to find out:
So I did a bit more digging. The Department for Communities and Local Government had, in fact, published an "explanatory note" to the figures. And, looking at footnote 2, we can finally establish what the definition of a "troubled family", on which the Prime Minister's numbers were based, actually is. It is a family which satisfies at least 5 of the following 7 criteria:
a) no parent in work
b) poor quality housing,
c) no parent with qualifications,
d) mother with mental health problems
e) one parent with longstanding disability/illness
f) family has low income,
g) Family cannot afford some food/clothing items