Policing and Racial Equity

The Chattanooga Police Department is committed to its mission to keep you, your family, and our community safe through service with integrity.  This includes achieving the CPD vision of a department that is both respected and trusted by ALL segments of Chattanooga's diverse community.  Part of building this trust includes constantly challenging ourselves to view the data through an equitable lens to check if our services have a disproportionately negative effect on historically oppressed communities of color in Chattanooga.  The data is not a solution but merely an indicator for current potential racial inequalities in the system. 

What data we're looking at:

  • Citations: Often in lieu of an arrest, Citations are given for minor to major traffic violations.  Research has shown that Black, Indigenous, People of Color (BIPOC) drivers are more likely to receive economic citations such as failure to provide proof of insurance or license, but are less likely to be cited for moving violations such as speeding or not stopping at stop signs.  CPD continually looks at citation data to observe if this trend occurs and also if BIPOC residents are cited at a higher proportion than White residents.
  • Arrests: Arrests have some of the most negative impacts on an individual's well-being and future life, thus data should be constantly examined on who, where, and what for arrests are occurring in Chattanooga.  The publicly available data on arrests accounts for 82% of arrests as juvenile, child abuse, and domestic violence arrests are not made public.  A meta analysis of research indicates that BIPOC residents have a higher probability of being arrested than White residents.
  • Use of Force: Nationally, BIPOC have higher probabilities of death in a use of force incident than White residents.  This is amplified even more when specifically looking at BIPOC Men. CPD must look locally at our data to observe if use of force trends compare to national statistics.
  • Citizen Complaints: CPD interacts with residents hundreds of thousands of times per year through 911 responses and non-official encounters.  Through these interactions, a very small minority result in official complaints submitted by citizens to the Internal Affairs department.  Though it is a small number of complaints, these must be examined to look for trends in officer behaviors and the citizens submitting the complaints.

At a High Level

We begin by looking at extremely high level data.  The below maps and visualizations break down summary statistics at a City of Chattanooga level and census tract level.  The period by which data is aggregated is from January 1, 2018 to present.  The first map below contains information on arrests broken down by census tract.  One key aspect to consider is how often an arrest occurs when a 911 call is made.  According to the data below, the typical percentage of 911 calls that end in an arrest are around 2%-6% of all calls the CPD responds to.
Though approximately 2%-6% of 911 calls result in an arrest, only a minimal amount involve use of force.  Looking broadly at the number of 911 calls CPD responds to and calculating what percent involve use of force yields an estimate of about 0.05%-.25% of 911 calls. 

High Level Comparison

The graph to the right is a simple total count since January 1, 2018 of how 911 calls, citations, arrests, use of force, and citizen complaints compare in the city overall.  This visualization paints a picture of the strikingly low percentage of 911 calls that involves use of force or citizen complaint. Roughly 0.13% of 911 calls involve any sort of use of force and 0.02% of 911 calls result in a citizen complaint.  We are unable to compare this number to peer cities due to the lack of publicly available data.  

Citations

As stated previously, citations are often given in lieu of an arrest for minor infractions in violation of local and state laws.  These ideally operate as negative incentives to change behavior.  Logically, if you receive a speeding ticket with a monetary penalty, you are less likely to speed in the future.  There is evidence based research that also supports targeted traffic enforcement for speeding and other safety related violations leads to reductions in vehicle accidents.  The below data attempts to breakdown the different views of citations in Chattanooga and who citations impact.

Cited Individuals

The chart to the right is a breakdown of all cited individuals since January 1, 2018.  Ideally, these numbers should somewhat mimic the Chattanooga population which according to ACS 2019 estimates is 61.7% White Alone and 32.6% Black or African American.  The numbers do not match perfectly, but do indicate a pretty close proportional citation rate.
Research has shown racial disparities can occur when comparing citation volumes broken down by race for different traffic stop/violation types.  Safety stops in this case are defined as traffic light violations, stop sign violations, speeding violations, seat belt violations, and other types of violations related to safety.  The other type, economic stops, are often a result of an out of date city sticker, lack of insurance (financial responsibility), or out of date auto registration.  Typically, there are disproportionate citation rates for economic citations for BIPOC communities and there are no links to decreases in traffic accidents due to these citation types.  
The two charts below show the distribution of cited individuals broken down by safety violations and economic violations.  Per the data, the safety violations appear consistent with Chattanooga's population.  The data also reveals Chattanooga matches similar research for economic violations where as there is a significant disproportionate amount of economic violation only type traffic stops for the BIPOC community.

Safety Violation Distribution

The below chart is the distribution of citations where at least one violation that resulted in a citation is related to safety such as speeding, seat belt, stop sign, improper turns, red light violations, and other safety related violations.

Economic Violation Distribution

The below chart is the distribution of citations where ALL violations in one citation instance are not related to safety such as financial responsibility, auto registration, improper display of plates, and driver's license violations.

Citations Dashboard

In order to better understand the details of this data as well as view year or year changes, please select the tile to the right to dive deeper into the citation related data.

Arrests

As stated previously, being arrested can have significant impacts on an individual's employment, wealth, and other socioeconomic outcomes.  Thus, the Chattanooga Police Department remains diligent in observing who is negatively impacted by arrests and what charges are applied in individual arrests.  It is a top priority to arrest individuals involved in violent crimes, but the data below shows these arrests represent a fraction of overall arrests by CPD.

Arrested Individuals by Race

The chart to the right is the distribution of individuals arrested since January 1, 2018 by race.  For reference, the Chattanooga city population according to ACS 2019 estimates is 61.7% White Alone and 32.6% Black or African American.  Clearly from the simple distribution, to the right, there is a clear disproportionate amount of arrests.
To simply look at straight distributions is not enough, we must look at what individual charges occur on these arrests to see if they are disproportionate across the board or if it varies by arrest charge types.  The chart below pulls from the public arrest charge data and only contains the 25 arrest charges which accounts for approximately 66.5% of all charges in the data set.  The dotted line indicates the Black or African American population in Chattanooga at 32.7%.  There are striking disproportional arrest charge rates of driving on a revoked license and driving on a suspended license.  
To go one step further, we can look at what charges in total are levied against an individual during an arrest.  The chart below shows similar data as above, but breaks it down by all charges levied in one arrest instance.  Often times, a resident may be charged with multiple statute violations in one arrest, as evident in the data below.  The top three total charges seem to be Individual Serving Warrant, Individual Shoplifting, and Multiple Serving Warrants.  Interestingly from the data below, we again see the disproportionate affect of traffic charges (not including Driving Under the Influence), misdemeanor drug violations, and a high proportion of arrests for Trespass of Real Property for the BIPOC community.
Diving deeper into specific charges related to Serving Warrant, it appears the most common charge is failure to appear.  Legally, when there is a Failure to Appear on a warrant, CPD is required by law to arrest an individual.  The two other most common charges related to a Serving Warrant are Theft All Other Larceny and Driving on Revoked License.

Arrests Dashboard

In order to better understand the details of this data as well as view year or year changes, please select the tile to the right to dive deeper into the arrest related data.

Use of Force

Though the data at the top of this dashboard shows a very small fraction of 911 calls that CPD responds to involves use of force, it is still important to understand how those use of force occurrences are distributed.

Use of Force Disposition

Every police involved use of force occurrence must make it's way through several reviews.  This includes use of force types from deploying less lethal weapons and using handguns to restraining an individual.  Approximately 97% of Use of Force incidents are In Policy outlined HERE.  A small fraction, 2%, are Out of Policy and another 1% become Internal Affairs cases due to the nature of the Use of Force.
Though use of force occurrences are extremely low as a percentage of all interactions CPD has with residents, it is important to observe if there is a disproportionate rate of use of force for BIPOC residents compared to White residents.   There is a clear disproportionate percent of BIPOC individuals involved in a Use of Force occurrence compared to census estimates.  However, this distribution closely matches the distribution of arrested individuals by race.  In the chart below, when there are multiple values separated by commas, this indicates multiple individuals involved in the Use of Force occurrence.

Internal Affairs Dashboard

In order to better understand the data available on Internal Affairs (IA) investigations, please select the tile to the right to dive deeper into the IA related data.

Citizen Complaints

Another strong bellwether indicator for interactions with residents are citizen complaints filed with Internal Affairs.  These are official complaints that can be filed from an officer being discourteous to more severe criminal actions an officer is alleged to be involved in.  Though there is an extremely low number of citizen complaints, all are taken seriously and investigated thoroughly by the Internal Affairs division.  The below chart shows the common allegations related to complaints and their findings since January 1, 2018.  A finding of Sustained indicates there was enough evidence to support the allegation; Unfounded and Not Sustained indicate there was no evidence to sustain the allegation or there was not enough evidence, respectively.  Notably, Discourtesy seems to have the highest count of allegations, but Improper Procedure actually has the highest count of Sustained allegations.

Overall Dispositions

The overall dispositions on citizen complaints provides a high level view of the incident.  If just one allegation is found to be sustained on a complaint, the overall disposition is marked as unstained. 

Internal Affairs Dashboard

In order to better understand the data available on Internal Affairs incidents, please select the tile to the right to dive deeper into the IA related data.

Sources

Below are some sources used in the above dashboard beyond the data.
  1. Kochel, Tammy Rinehart, David B. Wilson, and Stephen D. Mastrofski. "EFFECT OF SUSPECT RACE ON OFFICERS’ARREST DECISIONS." Criminology 49.2 (2011): 473-512.
  2. Greenleaf, Richard G., et al. "Race-based decisions: Traffic citations and municipal court dispositions." Justice Policy Journal 8.1 (2011).
  3. Edwards, Frank, Hedwig Lee, and Michael Esposito. "Risk of being killed by police use of force in the United States by age, race–ethnicity, and sex." Proceedings of the National Academy of Sciences 116.34 (2019): 16793-16798.
  4. Fliss, Mike Dolan, et al. "Re-prioritizing traffic stops to reduce motor vehicle crash outcomes and racial disparities." Injury epidemiology 7.1 (2020): 3.
Here are direct links to datasets on the ChattaData platform you can explore yourself and create visualizations with.
  1. Public Arrests - Data on individuals arrested by CPD and their charges since January 1, 2018
  2. Public Arrest Charges - Data on individuals arrested by CPD and their individual charges since January 1, 2018
  3. Citations - Data on individuals cited by CPD since January 1, 2016
  4. Citation Details - Data on individuals cited by CPD and their individual violations since January 1, 2012
  5. Police Incidents - Data on police incidents from 911 calls that result in Police reports being created
  6. Internal Affairs Incidents - This is the most high level detail of an Internal Affairs Incident where each row of data is a singular incident or case file with some summary information.
  7. Internal Affairs Incidents Detailed - This is a slightly more detailed view of Internal Affairs Incidents where each row of data is an individual involved in an incident or investigation.
  8. Internal Affairs Allegations - This is a detailed data set on all allegations made against CPD Officers during the course of an Internal Affairs allegations.