The University of Iowa-based Iowa Policy Research Organization (IPRO) released a report Monday that suggests Iowa City’s 21-Ordinance has had no measurable effect on PAULA arrests since its implementation in June 2010. Their data shows that PAULA arrests have been decreasing at a rate of 10 per month since 2004. The report also indicates that the ordinance has contributed to a rise in Disorderly House charges, a finding that directly contradicts statistics available on the 21 Makes Sense website showing that such charges have dropped 26 percent since the ordinance was adopted.
Prof. Rene Rocha, IPRO’s faculty supervisor, says this study is a more accurate measure of 21-Ordinance-related crime statistics than previous studies because it analyzes monthly data trends over a 10 year period.
“Basically, what previous studies have done is looked at, say, the raw number of PAULAs before and after the 21-Ordinance,” Rocha said. “We are not reporting summary statistics. We are statistically accounting for trends across time and then looking at changes in trends across time after the 21-Ordinance. In the report I reference something called the AutoRegressive Integrated Moving-Average (ARIMA), and that’s the statistical technique used in our analysis. It’s different and more sophisticated than simply reporting some raw numbers of violations before and after the ordinance.”
Tom Rocklin, one of the 21 Makes Sense organization’s Co-Chairs and Vice President for Student Life at the University of Iowa disagrees with the IPRO’s analysis.
“Not surprisingly, I think our results (or those published by the City, which made decisions different from either IPRO’s or ours, or those published recently in the Gazette, using another set of decisions) tell the story more accurately,” Rocklin wrote in an email to Little Village.
Rocklin points out that the IPRO report looks primarily at underage individuals charged with PAULAs rather than a total number of drinking charges issued. According to Rocklin, if the total number of alcohol-related arrests had been taken into account by the IPRO during their study, they may have come up with very different results.
“We used simple counts,” Rocklin said, noting that IPRO’s use of ARIMA may not tell the whole story. “IPRO also chose to use percentage of public intoxication charges to under 21 year olds. That eliminates any effect of the actual total number of charges. Each is a relevant variable for policy analysis. Total number might demonstrate that many fewer out-of-towners come to Iowa City to drink, reducing the number of drunk people on the street. That’s relevant to community members.”
The IPRO report also notes a decline in OWI offenses by individuals under 21 since the implementation of the 21-Ordinance.
The discussion section of the report states that, “OWI incidents by minors declined in Iowa City. It would make sense that if parties are closer to most students’ residences, they would be more likely to walk to these parties and less likely to drive, and drive drunk. So, in these senses, it makes sense that the data show these intuitive effects.”
Once again, Rocklin disagrees with the IPRO’s data analysis and points to out-of-towners as the possible source of statistical variation.
“I think it much more likely that OWIs among minors went down because fewer minors come to Iowa City from out of town,” he said. “My observations and conversations with students suggest that driving to a house party is extraordinarily rare. I don’t know where a party-goer would park on South Johnson after midnight.”
On November 5, Iowa City residents will once again get to weigh in on the issue when the 21-Ordinance appears on the ballot for the Iowa City City Council election. Early voting has already begun, and will continue at satellite locations throughout Iowa City in the lead up to the election.