Tuesday, 11 November 2014

Big numbers: domestic violence edition

Simon Collins at The Herald reports on some problems in Suzanne Snively's estimates of the social costs of domestic violence.
Sir Owen Glenn's family violence inquiry has stumbled again, producing a $7 billion estimated cost of family violence based on the mis-reading of a key research paper.
A report by economist Suzanne Snively and Wellington theatre student Sherilee Kahui, published by the inquiry yesterday, said family violence cost New Zealand between $4.1 billion and $7 billion a year - up from Ms Snively's last estimate in 1994 of just $1 billion.
It looks like they attributed the full high-end costs to the greater number of people experiencing more moderate forms of abuse. This isn't to diminish that experience, but there are gradations of experience and gradations of cost.
Inquiry spokeswoman Marie McNicholas declined to comment on the latest mistake and referred questions to Ms Snively. Ms Snively said the data was prepared by Ms Kahui.
Ms Kahui said the $7 billion "high-end" figure was not in an early version of the study, which initially included only the "low-end" estimate of $4.1 billion and what is now described as a "moderate scenario" of $4.5 billion.
The high-end estimate was added after experts in Auckland and Wellington said they believed the true domestic violence victimisation rates were higher than the "moderate scenario" rates of 18.2 per cent for women and 1.9 per cent for men.
"We were struggling to find empirical evidence of an estimate that would be higher than 18.2 per cent," Ms Kahui said. "So it was about finding something higher."
Jeepers. Kudos to Ms. Kahui for pointing out that there was a quest to find a big number.

I note that Suzanne Snively also authored the PWC report on Adult and Continuing Education that estimated very large benefits from Adult and Continuing Education by assuming that anybody taking a night cooking course would be 50% less likely to commit any crime.

Congrats too to Simon Collins for catching this. I didn't have time to look through the report yesterday when I saw the big number floating around; nice to see that others have started sniffing out this stuff.