Jan 14 2013
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Public Health Law Research Annual Meeting: Q&A with Diana Silver

PHLR Annual 2013

Public Health Law Research (PHLR), a program of the Robert Wood Johnson Foundation, will hold its annual meeting in New Orleans this week. NewPublicHealth will be on the ground covering sessions on research in public health law as well as posting interviews with conference speakers including Thomas Farley, MD, MPH, Health Commissioner of New York City and Pamela Hyde, JD, administrator of the federal Substance Abuse and Mental Health Services Administration.

In advance of the conference, NewPublicHealth spoke with Diana Silver, PhD, MPH, assistant professor of public health at the Steinhardt School of Culture, Education and Human Development at New York University. Silver’s research looks at the impact of public and private services on health and well-being for children and families, especially in urban America. Her presentation at the PHLR annual meeting is called “Are More Laws Better?” with a specific  look at what has happened to traffic fatalities between 1980 and 2009 as new laws have been implemented in some parts of the country.

NewPublicHealth: Tell us about your research on laws and traffic fatalities.

Diana Silver: The motivating idea here was that there are multiple laws at the state level that govern traffic safety. Some deal with alcohol, some deal with restraining children one way or another in the car, some are about the vehicle itself such as seatbelts or speed limits. The laws vary at the state level, and they create, in some sense, really different environments that people are exposed to. We have now categorized across 30 years 25 different laws in all 50 states. 

What we found is that there are some laws that virtually all states have adopted, mostly because there’s been a federal mandate to do so, like a minimum legal drinking age. But many laws vary across states, and so we were interested to find out what factors predicted whether a state would pick up new laws and how quickly they would do that. Then, how do these different packages predict, or are they associated with reductions in motor vehicle fatalities?

NPH: How was your research different than other research that looks at this data?

Diana Silver Diana Silver, New York University

Diana Silver: A lot of our funding was directed at pulling the data together. Much of this is publicly available data, but the data, once you look at it, are incomplete in one way or another.  They’re missing states, they’re missing years, the laws themselves are coded poorly, and I think one of the great things about PHLR was that with their training and with their support we were able to gather these laws by doing original legal research. We now are able to characterize these environments and when we looked at the changes in motor vehicle fatalities, we asked: if you give every state a law, do more laws matter? Well, yes, they do. They’re associated with reductions in fatalities across states over time, and different packages of laws actually do have independent effects on the motor vehicle fatality rates.

One of the things we did was to compare states with 25 laws, and others with fewer to try to understand how the numbers of laws affects these outcomes. And we saw that if you have the total number of laws possible, you have a lower rate of fatalities. A one percent increase in total traffic laws is associated with about a 14 percent reduction in the state’s motor vehicle fatalities.   

We also found that if you look at the motor vehicle fatality rate for those under 25 years of age, for every increase in those laws that influence the alcohol environment, you see about a five percent decrease in the overall motor vehicle fatality rate. And this makes a lot of intuitive sense.  Most of these laws have been evaluated in either cross-sectional analyses or in single states, and the evidence base, while it’s strong, it’s not necessarily strong looking over time or looking across states in these ways, and I think that’s been one of the great contributions we’ve been able to make. We’ll be exploring more of this in an NIH-funded study that we were able to get funded building on the PHLR work that we did and we’re really excited about that.

NPH: What do you want meeting attendees to take away from your presentation at the PHLR conference?

Diana Silver: What I’m hoping to do is to step back a little bit and have the audience think about public health law environments. There are many laws that influence single behaviors, such drinking and driving. There are multiple kinds of laws that do affect drinking and driving, and rather than evaluating each individual law or a single contribution, let’s think about, from a public health perspective, how do these laws interact? What is their cumulative impact on reducing drunk driving? What’s the best bang for the buck you can get in different environments when you’re thinking about adding any of these types of laws? So I think it’s about shifting our attention upstream a little.   

We’ve also, in this dataset, with PHLR support, not only gathered laws about traffic but we’ve also been able to fill in gaps on tobacco control laws and immunization regulations, particularly the exemptions to immunization laws across all 50 states and a few other things around reproductive health.  Here, again, we’re going to try and think about are these public health issues, are they silos?  That is, are some states really great about tobacco and really not particularly aggressive around alcohol?  Or, in fact, are there really aggressive states that are interested in using the law to protect people’s health more aggressively than other states? It doesn’t matter which domain they are. These are tools that they use. They tax alcohol highly, they tax tobacco highly, they keep speed limits low, they don’t exempt people from immunization requirements, etc. Or is it just actually that there are some states where the injury control people are terrific, but it’s really the tobacco folks that need a lot more support. I think trying to understand that from a public health perspective is a really different way of thinking about it. It’s really about population health and less about these kinds of siloed specific health problems. 

NPH: In what way do you think your work might impact other public health areas that rely on law?

Diana Silver: I think there are a few ways. One is to point to the idea of diffusion and adoption.  We want to understand the interaction among states as learning laboratories, and I think that’s an important piece of the work that we have been doing here. States don’t operate totally in a vacuum and we want to understand that process a little bit better, ideally with the idea that we can therefore facilitate the adoption of these evidence-based approaches much more quickly. We want to understand those diffusion patterns and we want to understand what things predict, whether or not states will, in fact, adopt new laws. That’s pretty poorly understood at this point.

And a second frontier is really trying to understand something about how these laws are put into practice – how they’re used, how they’re enforced, what the complications are and just what the resources are in a state to enforce those things. We can write the best laws we want and we can even diffuse those, but if there is not a strong enforcement mechanism we’re not really going to achieve their full potential.  

Tags: Disease Prevention and Health Promotion, Injury Prevention, Public and Community Health, Public health law, Q&A, Transportation