Kanuk's Open Salon Blog

When “Moderate Republican” is the new “Socialist”

Thu, 17 May 2012 19:05:55 -0400

Earlier today, my wife and I saw a TV ad that amazed both of us. We never thought the word moderate would come to mean socialist.

Provided to you courtesy of David Dew-Hurt Texas

Update (May 18, 2012):

Now, the Texas Conservative Funds claims that Dewhurst's oppenent, Ted Cruz, is also not conservative enough:

Even Republicans say it: the “single-payer” system works!

Thu, 10 May 2012 15:05:44 -0400

Who would have thought that staunch Republicans and conservatives, unbeknownst to them, finally realized the benefits of the “single-payer” system? Interestingly, Texas A&M University announced yesterday that, in order to save $1.7 million in health care costs every year, the university’s Board of Regents has decided to consolidate all employees into a single health care insurance plan.

The move will apparently not only save A&M close to $2 million annually, but the monthly premiums are expected to be greatly reduced for all university employees. Some will see a 41% reduction in health care costs. No kiddin’

As described in the News Release below, the new Single A&M Care Plan won't have any negative impacts on getting access to existing medical services.

Just to be clear: this is not a true single-payer system, but one similar to Medicare (i.e., with deductibles and co-pays, etc.) (and managed by a private insurance company); hence putting the expression in quotes above.

What’s more striking?

This announcement corroborates what I have been discussing over the last three years:

Ballooning health care cost: is Medicare the culprit? (see figure below)

The case against the U.S. health care system

Let's Spread the Risk! (I mean Health care; Not Flu.)

As discussed in these posts, putting everyone into the same risk pool significantly helps in reducing health care costs. In short, this is what A&M is doing.

When will a similar proclamation be made at the national level?

The News Release:

Here's an example about how health care expenditures changed following the implementation of the single-payer system in Canada in 1971:

Blue line: US; Red line: Canada

“Stand Your Ground”: How does it stand up to history?

Sun, 22 Apr 2012 22:04:21 -0400

In my two previous posts (here and here) on Florida's "Stand Your Ground" law, I discussed the results of various (and relatively simple) before-after analyses I did using observational data. These data included the number of justifiable homicides, the total number of homicides and the number of homicides involving a firearm for the State of Florida. I also included national data on homicides to help refine the predicted values for some of these analyses. The results seemed to show that a significant increase in homicides involving firearms as well as justifiable homicides was observed after the enactment of Florida Statute 776.013 (3) in 2005.

Using a before-after study methodology can be tricky. You see, one of its primary assumptions states that external factors influencing the number of events (i.e., motor vehicle crashes, deaths, suicides, etc.) remain constant or unchanged for the entire study period (both for before and after periods). They usually cannot be all eliminated, but when they are known, the study design needs to be changed in order to minimize potential biases associated with the proposed analyses.

For this short post (I promise!), I therefore decided to focus my attention on these external factors. In order to accomplish this task, I extracted information about when specific laws and regulations related to gun control were introduced or enacted by the federal government between 1980 and 2010. I didn't have the time to find the same information for state and local regulations, particularly those enacted in Florida (other than the SYG law). It is therefore possible that some of these could have influenced the annual number of homicides, but I remain confident that their impacts are minor.

The primary Acts and pieces of legislations are tabulated below:

Relevant Gun Control Legislations Enacted Between 1980 and 2010 (source: http://www.infoplease.com/spot/guntime1.html#1990)

I again focused my investigation on Florida and the U.S. For this one, I used this nifty website to extract the data I needed to produce the figures below; it contained more years of data than the two websites I used previously.

Now, let's see how the number of homicides varies over time as a function of when the various Acts were introduced. I included the average number of homicides for each time period for discussion purposes.

Annual Homicides in Florida

(source: http://www.disastercenter.com/crime/flcrime.htm)

Annual Homicides for the U.S.

(Source: http://www.disastercenter.com/crime/uscrime.htm)

The figures above show very interesting results:

1) For both datasets, a very wide variation in homicides can be seen prior to the full application of the Brady Handgun Violence Prevention Act in late 1998 via the deployment of the NICS by the FBI. Afterwards, the variation around the mean becomes much much smaller (the coefficient of variation is in fact reduced by a factor equal to 2.5).

2) The Acts introduced in 1994 seemed to have started reducing the number of homicides in Florida and elsewhere in the U.S. Not many studies have examined the effects of the Brady Law, but those I found indicated a reduction in the number of crimes and/or homicides (see list below). Some reported a reduction in the number of suicides.

3) The "jump" seen between 2005 and 2006 in Florida is significant, as discussed before. In fact, the difference between the mean values is more than 6 times the standard deviation calculated for the 1999-2005 time period. This difference is beyond the random variations for observational data (usually below 3 standard deviations).

4) The time period I used for the before-after analyses appears to be adequate. All the analyses were done after 1999.

A sample of studies on the Brady Handgun Violence Prevention Act (and background checks):

Bowling, M., Frandsen, R.J., Lauver, G.A., Boutilier, A.D., Adams, D.B. (2010) Background Checks for Firearms Transfers, 2009-Statistical Tables. Office of Justice Programs. U.S. Department of Justice. Washington, D.C. (http://bjs.ojp.usdoj.gov/content/pub/html/bcft/2009/bcft09st.pdf)

La Valle, J. M. (2010) Re-Estimating Gun-Policy Effects According to a National Science Academy Report: Were Previous Reports of Failure Pre-Mature? Journal of Crime and Justice, Vol. 33, Issue 1, pp. 71-95.

Frandsen, R.J. (2010) Enforcement of the Brady Act, 2008: Federal and State Investigations and Prosecutions of Firearm Applicants Denied by a NICS Check in 2008, St. Louis, MO: Regional Justice Information Service.

Sumner, S.A., Layde, P.M., Guse, C.E. (2008) Firearm Death Rates and Association with Level of Firearm Purchase Background Check. American Journal of Preventive Medicine, Vol. 35, Issue 1, pp. 1-6.

La Valle, J.M. (2007) Rebuilding at gunpoint: A city-level re-estimation of the brady law and RTC laws in the wake of Hurricane Katrina. Criminal Justice Policy Review, Vol. 18, Issue 4, pp. 451-465.

Center to Prevent Handgun Violence (2000) Saving Lives by Taking Guns Out of Crime: The Drop in Gun-Related Crime Deaths Since Enactment of the Brady Law.

Thanks to Mishima666 for providing the link to the data I used above as well as for the useful discussions we had on this topic.

Added Homicides: More evidence against “Stand Your Ground”?

Fri, 20 Apr 2012 10:04:39 -0400

In my previous post, I examined the effects of the "Stand Your Ground" law on the number of justifiable homicides in the State of Florida. For this, I conducted a simple before-after analysis using data reported in the Tampa Bay Times. Despite the limitations associated with these data, the results seemed to show that the number of justifiable homicides increased significantly following the introduction of Florida Statute 776.013 (3) in 2005.

I decided to dig a little deeper on this subject. I was specifically interested in finding out whether or not the SYG law influenced the total the number of homicides covering the same time period I used in my first post. Not only was I able find the data I needed, but I was also able to uncover similar data for the entire country. The national data can be used to refine the predicted number of homicides by accounting for spatial and temporal variations (e.g., changes in the economy, policies affecting a large portion of the population, weather patterns, etc.). I won't repeat the study methodology and terminology here, but the avid reader can found them in the original post.

Using the Florida Department of Law Enforcement (see here) as well as the FBI (see here) websites, I extracted data on the number of homicides, the number of homicides involving a firearm, as well as the number of violent crimes. I decided to include those because one person who commented on my first post indicated that the SYG law could potentially influence violent crime rates. We'll see later if this is the case.

But first, let's examine the number of homicides, shall we?

The table below shows the number of homicides between 2000 and 2010 for Florida and the United States:

A preliminary assessment of this table seems to show a spike in homicides between 2006 and 2009. One attribute that may not be obvious, however, is that the proportion of homicides involving a firearm increased from about 59% in the before period to 67% in the after period (a change that is statistically significant). This change in percentages will become very important below.

As discussed in the first post, the data are better illustrated using figures. The first figure shows the number of homicides for Florida, while the second one focuses on the homicides that occurred at the national level.

Annual Homicides in the State of Florida (Source: FDLE)

Annual Homicides in the United States (Source: FBI)

The first figure shows that the annual number of homicides initially increased substantially between 2005 and 2007, but also decreased rapidly between 2007 and 2009. The homicides involving a firearm followed a similar pattern.

Interestingly, the same characteristic can be seen with the national data. However, in this case, the number of homicides starts increasing in 2004, but peaks in 2006 rather than in 2007. The decreasing rate is actually greater than the one observed in Florida (this is difficult to see on the figures).

In short, since a similar variation can be discerned in Florida and the rest of the U.S., a portion of the trend observed in the homicide rates in Florida can also be explained by factors influencing the murder rates for the entire country.

The question becomes: "How does the national trend affect the number of homicides in Florida?"

To answer this question, I again performed a before-after study for your benefit. This time, I conducted two analyses: with and without the national data. I removed the Florida homicides from the national data for the second analysis. We don't want to duplicate the counts, right?

The results for the total number of homicides are shown below:

Before-After Analysis for the Total Number of Homicides in Florida

The figure above illustrates that the national trend had a large impact on the total number of homicides. The observed increase changes from 22% (statistically significant) to about 2% (non-statistically significant). Overall, the analysis shows a marginal increase in the total number of homicides for the after period. Weird, isn't? There is probably a good reason, which I'll address at the end.

Now, let's look at the homicide data involving firearms.

The results are shown below:

Before-After Analysis for the Number of Homicides Involving a Firearm in Florida

The figure above demonstrates a much more clear-cut increase in the number of homicides involving a firearm. The national trend reduces the observed increase by about half, from 38% to about 17% (both being statistically significant). Although a very small increase was noted for the total number of homicides, a larger increase can be noted for those involving a firearm.

As noted above, the proportion of homicides caused by a firearm increased substantially in the after period. In this regards, it is important to note that the SYG law is strongly linked with the use of a firearm (concealed weapons). Thus, the observed increase in homicides caused by a firearm may not be surprising. Interestingly, CNN reported yesterday that the State of Florida intends to review its gun laws following the Trayvon Martin tragedy.

Again, there is definitely something that happened in 2005, which changed the characteristics of homicides in Florida.

Putting aside the homicides, let's focus on the violent crimes.

The raw data for Florida and in the U.S. are presented in the two figures below:

Annual Violent Crimes in Florida (Source: FDLE)

Annual Violent Crimes in the United States (Source: FBI)

Both figures show a similar tendency: a small decrease ending in 2004, followed by an increase peaking in 2006/2007 before coming down again. Using these data in the before-after study shows a small decrease of 5% (statistically significant) in violent crimes. However, when the national data are included in the analysis, the decrease becomes equal to a mere 2% (not significant). Including the national data indicates that the reduction in violent crimes observed in the U.S. is actually greater than the one noted in Florida.

What do these analyses tell us?

Well, here are my concluding points:

Accounting for the national data, the SYG law in Florida seems to be associated with an increase in the number of homicides involving a firearm, although the total number of homicides didn't increase significantly after 2005. The increase may be masked by a reduction in non-firearm-related homicides, which could perhaps be attributed to a national trend. The magnitude of the increase is more or less in line with the increase in justifiable homicides discussed in the previous post.
The reduction in homicides and violent crimes after the peak seen in 2007 is smaller in Florida than the decline noted at the national level.
The SYG law doesn't appear to have reduced the number of violent crimes in Florida (marginal at best).

Obviously, further work should still be done to examine these issues more closely. If someone pays me, maybe I'll look into them.

The usual caveat: other unknown factors combined with the SYG law could also be linked to the increase in homicides caused by a firearm. (We always need to write this kind of warning in our research reports and papers.)

There you have it, folks! Free of charge for your edification.

I know this was a long post. Sorry...

Update (April 22, 2012)

New post: "Stand Your Ground": How does it stand up to history?

Florida’s “Stand Your Ground” Law: A Statistical Analysis

Sat, 14 Apr 2012 10:04:49 -0400

Florida Statute 776.013 (3):

"A person who is not engaged in an unlawful activity and who is attacked in any other place where he or she has a right to be has no duty to retreat and has the right to stand his or her ground and meet force with force, including deadly force, if he or she reasonably believes it is necessary to do so to prevent death or great bodily harm to himself or herself or another or to prevent the commission of a forcible felony."

The Trayvon Martin tragedy has certainly struck a nerve with the American public, but among the myriad of newspaper articles and blog posts about the terrible death of Travyon, very few have actually discussed the "Stand Your Ground" law that initially allowed George Zimmerman to go free.

I was curious about the effects of the law myself, so I did some research. What I found is that the Tampa Bay Times (here) and the Washington Post (see here and here) have recently reported that the number of deaths associated with "self-defense/justifiable homicides" cases in Florida has significantly increased following the introduction of "Stand Your Ground" in 2005.

As expected, some people have been quick to dispute the data reported in these two newspapers. One of them, Mr. Walter Olson who is a senior fellow at the Cato Institute, took issue with the apparent increase in the number of deaths in an opinion piece he penned for The Daily Caller. His piece also contains several errors, but we'll get to that in a minute.

As most of you know by now, I'm in a line of work that requires analyzing the effects of interventions based on observational data (e.g., deaths, motor vehicle crashes, sick people, etc.). Currently, this analysis is performed with a methodological approach known as the before-and-after study, which is favored over other approaches because the observational data are analyzed for the same location, but at different points in time. The before-after study also allows for a better control of external factors that may affect the frequency of events (other than the intervention itself).

Since this is a blog post and not an academic paper, I won't bore you with the details related to the theory behind before-after studies (which I helped developed). I included a list of resources at the end for those interested.

For this kind of study, the primary goal consists of predicting the number of events in the after period if the intervention had not been implemented. Then, the secondary objective aims at comparing this predicted value with the observed number of events for the entities under study. Depending on the availability of the data, the before-after study considers the length of the time periods (before and after), changes in exposure (such as the prevalence of firearms for example) as well as local and regional time-trend effects if data can be collected for what we call the "control group." As with any methodology, there are limitations, but those won't affect the results discussed below.

Using the data provided by the Tampa Bay Times, I conducted a "simple" before-after analysis to specifically determine whether the number of permissible homicides has increased after the introduction of the SYG law (Florida Statute 776.013 (3)). The raw data are illustrated in the figure below:

The figure above shows that, on average, Florida experienced about 34 justifiable homicides per year for a total of 206 deaths in 6 years. In the after period, the annual death rate was about 85, which means that for the first four years, 333 justifiable killings were recorded (note: I didn't use the 2010 data because it wasn't complete). Even without using sophisticated analysis, there's a clear pattern that emerges from the raw data alone: there is an obvious increase in the number of deaths after 2005.

So, we definitely have more deaths. The important question now becomes, "Is the observed increase statistically significant or is it just a fluke?"

For that, I used the before-after methodology I described previously. I present the results in the table below:

The results shown in the table above illustrate the following:

There has been a very strong statistically significant increase (t-value=6.64) in the number of deaths.
The increase in justifiable homicides increased 2.5 times.
The introduction of the law has caused close to 200 more homicides following its enactment in 2005.

The results are actually better illustrated in the figure below:

The figure above shows that if the SYG was not enacted, we would have expected to see about 137 justifiable homicides during the first 4 years. However, 333 deaths were observed for the same time period.

In short, the table and figure clearly illustrate that the "Stand Your Ground" law has had a significant effect on the number of deaths at the 1% significant level. (Note: this means that there is only 1% chance that the increase observed in the number of deaths WAS NOT caused by the SYG law; the difference is statistically significant because the confidence intervals don't touch each other.)

In his Daily Caller piece, Mr. Olson indicated that the analyses reported in the WP contained serious methodological flaws. First, Mr. Olson claimed that the increase noted in data does not reflect the overall reduction in homicides rates for the entire state that has been observed between 2000 and 2010. Unbeknownst to Mr. Olson, if he had incorporated the general state-wide reduction in the analysis, the increase observed in the after period would be even larger than those presented above. In other words, the outcome would the complete opposite what he's claiming.

Secondly, Mr. Olson reported that the original data described above included police and other related shootings. The revised data lowered the annual average to 12 and 36 homicides in the before and after periods, respectively (also documented in one of the two WP articles). However, even if these revised numbers are used, the overall outcome of the before-after study remains the same. The difference is still statistically significant at the 1% level (I checked).

Finally, according to Mr. Olson, the characteristics of the data changed in the after period, in which several justifiable homicides may have been erroneously attributed to the newly introduced law. This may be a valid point. Nonetheless, although it is very difficult to properly validate each observation, removing a third of the deaths (from the 333) would still show a statistically significant increase in the number of homicides at the 1% significant level (to get a 5% significance level, about 50% would need to be taken away). One would have to remove more than 60% of the data after 2005 before the difference between the before and after periods becomes murky.

The bottom line is that if I were given this dataset without knowing its sources, I would positively conclude that what happened in 2005 significantly increased the number of events. I'm certain that if the data and subsequent analysis represented, say, the effects on car crash deaths from increasing the legal Blood Alcohol Content level from 0.08% to 0.10%, very few would be questioning the results.

Additional resources:

Cook, R., Wei, W., 2002. Selection effects in randomized trials with count data. Statistics in Medicine 21, 515-531.

Davis, G., 2000. Accident reduction factors and causal inference in traffic safety studies: a review. Accident Analysis & Prevention 32, 95-109.

Hauer, E., 1997. Observational Before-After Studies in Road Safety. Pergamon Publications, London.

Lord, D., Kuo, P.-F., 2012. Examining the effects of site selection criteria for evaluating the effectiveness of traffic safety improvement countermeasures. Accident Analysis & Prevention 47 , 52-63.

Park, E., Park, J., Lomax, T., 2010. A fully Bayesian multivariate approach to before- after safety evaluation. Accident Analysis & Prevention 42, 1118-1127.

Persaud B., Lyon, C., 2007. Empirical Bayes before-after studies: lessons learned from two decades of experience and future directions. Accident Analysis and Prevention 39, 546-555.

Update (April 18):

I was able to find crime data for the entire State of Florida and I will write a new post within the next few days. This post will include all murders and homicides involving a firearm between 200 and 2010. The results will be very surprising. Stay tuned!

Here it is:

Added Homicides: More evidence against "Stand Your Ground"?

Update (April 30):

A new post on this subject: "Stand Your Ground": How does it stand up to history?

This figure is discussed in more details: