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Washington Crime Analysis Project

This data analysis project is dedicated to discovering, analyzing, and visualizing crime data in Spokane, WA and around the state. Informed residents can make better decisions about where to live, raise families, work, and play in our wonderful city with up-to-date information on crime. With data in-hand, residents can engage actively and factually with local leaders and law enforcement. Using Computer Statistics (CompStat) data provided by Spokane Police Department (SPD) we're able to analyze crime that has already happened, discover trends in the data, and make predictions.

Currently, the SPD makes weekly CompStat reports available each Monday. Reports cover reported crime for the prior week in PDF format, broken down by policing districts. We scrape the PDF files, extract data, and transform it into a format useful for analysis and visualization.

  1. Overall Statistics
  2. Seasonality
  3. Police District Statistics
  4. Types of Offenses
  5. Lunar Phases
  6. Data Sources
  7. Data Limitations
  8. Violence Classifications
  9. Contact

Overall Statistics

Looking at overall statistics gives us a good starting point from which to explore crime over time and specific types of incidents. From September 2017 onward we see an overall downward trend in reported crime:

CompStat Total Offenses

By Year

We have CompStat data for full years beginning in 2018 for comparison:

Year Total Incidents Percentage Change Per Capita (100k)
2018 17418 NA 7591
2019 14434 -17.13 6291
2020 13321 -7.71 5806
2021 12125 -8.98 5284
2022 12627 4.14 5503
2023 13178 4.36 5743
2024 7664 NA NA

While CompStat data does exist prior to 2018, the reporting standards changed and some reports are missing. I'm not able to make accurate comparisons with years prior to 2018.

By Month

Total offenses by year and month:

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 1498 1235 1163 1077 1087 1132 976
02 NA 1186 916 1100 831 1177 1042 980
03 NA 1311 1080 1008 950 1195 969 1053
04 NA 1309 1305 1045 923 1101 984 949
05 NA 1524 1423 1044 991 1120 1190 1031
06 NA 1538 1312 1109 1011 1009 1207 942
07 NA 1656 1358 1205 1025 860 1217 1110
08 1277 1558 1300 1243 1114 910 1245 623
09 1290 1449 1226 1181 1151 891 1126 NA
10 1376 1543 1099 1209 959 1147 1010 NA
11 1418 1479 1049 1013 1010 1082 1011 NA
12 1454 1367 1131 1001 1083 1048 1045 NA

Here are the average daily incidents by month:

Spokane Average Daily Incidents by Month

By Incident Type

The majority of crime in Spokane is non-violent, though assaults, robbery, and other violent crimes do occur with some regularity:

ARSON ASSAULT BURGLARY DEFRAUD PUBLIC UTILITY DRIVE-BY HARASSMENT HOMICIDE INTIMIDATE MANSLAUGHTER MURDER POISON RAPE ROBBERY TAKING VEH. THEFT VEH. THEFT VEH. PROWL VEH. TRESPASS VEHICULAR ASSAULT
2018 41 853 2150 0 18 63 1 40 0 8 0 301 310 70 11649 1623 258 3 30
2019 42 729 1858 0 19 70 0 4 0 5 0 217 290 52 9912 1205 10 0 21
2020 99 663 1949 0 26 52 0 0 1 10 1 190 266 31 8937 1072 0 0 24
2021 101 713 1699 0 30 64 0 0 0 10 1 219 260 63 7865 1081 1 0 18
2022 58 701 1658 0 57 68 0 1 0 14 0 192 275 77 7889 1610 0 0 27
2023 82 750 1825 1 41 104 0 1 0 9 1 202 304 55 8332 1447 0 0 24
2024 76 457 918 0 23 90 0 0 0 7 1 123 205 30 4990 731 0 0 12

Here's both types of crime shown over time:

Non-Violent & Violent Crime

Of non-violent crimes, theft is the most common. This includes shoplifting, burglary (residential and commercial), and motor vehicle thefts.

Seasonality

When we're looking at events as they happen over time we must consider seasonality. Crime in Spokane definitely follows seasonal trends occurring throughout the year. We can use this seasonality to make predictions and give context to increases or decreases in crime. Data that follows a seasonal trend can be broken down ("decomposed") into its consituent parts. Here's a decomposition of overall crime data:

Overall Decomposition

The "seasonal" section of the plot above shows an obvious, repeating cycle that occurs each year. There's also a downward trend line. Once we've identified seasonal cycles it's possible to visualize what crime is doing independent of the expected change:

Overall Offenses, Seasonally Adjusted

Police District Statistics

The city is divided among eight policing districts, with four (P1, P2, P3, P4) in the "North Police Service Area", and the other four (P5, P6, P7, P8) in the "South". The north and south service areas are separated geographically by the Spokane River. Some offenses are noted as occurring in an "OTH" district with no amplifying information given. Districts designated "SPA", "SPB", "SPC", and "SPD" had also been used in the past but no information is given in the CompStat reports indicating what areas represent. Sometimes, an offense will be listed with no district in the weekly reports, possibly due to a data entry error. There was a spike in missing district information beginning in late 2021 and continuing into 2022.

Here's a graph of offenses with missing district information:

Missing police district offenses

In fact, there are more "NA" reports in 2022 than any other district:

Offenses by Police District, 2022 YTD

With that much data missing I'm not able to accurately visualize the count of crimes per-district for late 2021 or 2022. I've emailed SPD about this missing data but have yet to hear back. From September 2017 onward, districts P1-4 have the highest overall counts of reported crimes:

Offenses by Police District

Non-Violent Crime

Most crime in Spokane is non-violent. These offenses include burglary, motor vehicle theft, and "ordinary" theft.

Theft

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 1007 817 769 761 693 683 634
02 NA 783 616 755 528 793 683 651
03 NA 902 736 662 618 794 606 701
04 NA 901 919 675 601 736 638 606
05 NA 1006 993 693 642 722 752 655
06 NA 1042 898 721 684 608 752 601
07 NA 1118 924 787 654 479 747 726
08 918 1006 906 856 718 471 710 416
09 862 977 853 820 703 533 763 NA
10 935 1029 756 856 578 685 654 NA
11 932 1017 715 648 642 694 668 NA
12 985 861 779 695 736 681 676 NA

Theft data table

Burglary

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 175 167 155 146 156 195 136
02 NA 118 117 141 118 128 121 115
03 NA 128 135 175 143 124 131 105
04 NA 173 171 160 117 129 132 119
05 NA 177 185 157 134 153 162 131
06 NA 171 170 166 146 154 163 104
07 NA 197 179 187 137 114 150 133
08 148 215 162 149 151 152 161 75
09 153 193 154 171 169 127 149 NA
10 159 203 146 172 148 151 141 NA
11 184 189 137 162 154 144 148 NA
12 160 211 135 154 136 126 172 NA

Burglary data table

Motor Vehicle Theft

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 165 91 127 81 129 131 90
02 NA 133 93 107 66 148 105 85
03 NA 120 100 81 56 125 113 111
04 NA 96 91 97 72 119 89 97
05 NA 140 115 70 97 119 139 121
06 NA 140 116 93 45 112 139 87
07 NA 136 117 95 94 146 158 92
08 82 148 96 88 116 165 227 48
09 124 113 86 82 133 119 86 NA
10 123 137 92 73 106 169 86 NA
11 152 143 92 97 114 126 80 NA
12 144 152 116 62 101 133 94 NA

Motor vehicle theft data table

Violent Crime

Violent crime includes assault (vehicular and otherwise), drive-by shootings, sexual assault, robbery, intimidation with a weapon, and carjacking.

Robbery

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 26 28 23 13 25 15 27
02 NA 24 17 22 24 20 24 25
03 NA 19 21 28 17 31 20 32
04 NA 15 19 24 26 21 27 26
05 NA 15 22 17 19 25 31 26
06 NA 21 24 21 28 30 29 24
07 NA 41 27 29 22 27 45 30
08 18 32 28 25 21 16 30 15
09 21 34 28 23 25 19 22 NA
10 20 28 25 24 22 23 24 NA
11 19 23 26 10 24 22 24 NA
12 34 32 25 20 19 16 13 NA

Robbery data table

Assault

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 59 66 62 43 52 60 48
02 NA 68 43 45 52 53 61 63
03 NA 69 52 37 74 63 52 57
04 NA 66 69 54 53 52 58 51
05 NA 97 73 70 65 48 70 46
06 NA 81 64 61 61 65 74 76
07 NA 82 74 71 75 52 84 71
08 58 82 67 67 60 72 65 45
09 62 63 70 46 60 57 57 NA
10 58 81 48 44 66 77 64 NA
11 55 49 50 59 43 51 58 NA
12 65 56 53 47 61 59 47 NA

Assault data table

Sexual Assault

Month 2017 2018 2019 2020 2021 2022 2023 2024
01 NA 17 27 14 16 17 14 11
02 NA 19 18 11 19 14 21 14
03 NA 24 20 11 31 21 17 13
04 NA 25 18 14 24 18 18 21
05 NA 28 20 18 15 21 19 21
06 NA 41 21 22 23 19 20 19
07 NA 22 18 14 12 15 10 13
08 11 31 24 20 16 11 17 11
09 18 30 16 21 26 18 22 NA
10 32 25 14 20 11 13 15 NA
11 28 20 12 14 15 13 12 NA
12 26 19 9 11 11 12 17 NA

Sexual assault data table

Lunar Phases

Despite popular sayings like, "must be a full moon out, people are being crazy!", the moon's phase has no noticable affect on crime in Spokane. In fact, crime has been lowest in the last few years when the Moon is full:

Offenses per Lunar Phase, September 12, 2017 Onward

There is no significant difference in the amount of offenses between lunar phases.

Data Sources

There are many public resources that we leverage for data analysis. All are open and available to the public, though not always easy to find. Our data sources include the following:

  1. City of Spokane COMPSTAT reports
  2. City of Spokane OpenData GIS portal
  3. Spokane County ArcGIS portal
  4. HealthData.gov
  5. FBI's Uniform Crime Reporting (UCR) Statistics Tool
  6. U.S. Bureau of Labor Statistics Data Tools
  7. FBI's Crime Data Explorer (CDE)
  8. Spokane County 911 Communications Annual Reports

Data Limitations

There are limitations to the analysis that's possible using CompStat data provided by the city. While detailed information about Spokane crime does eventually get reported in the FBI's NBIRS program, there is often a year's lag or more before the public can download it. For example, 2018's data was made available in September 2019. As of January 2022, the most current data available is for 2020. It will likely be late-2022 or sometime in 2023 before 2021's data can be downloaded and analyzed. In the meantime, we only have the less-detailed CompStat data to work with. More in-depth analysis of the detailed FBI data will become a separate project when I have time.

Final Offenses

Weekly CompStat data may not accurately reflect the final offense someone is charged with. For example, simple assault may become homicide if the victim later dies from their injuries. Shoplifting could become "Retail Theft With Special Circumstances" if it's found the offender was part of a larger shoplifing ring. CompStat reports are not retroactively updated to reflect the final disposition of an offense. With that being said, there is more than enough data to identify trends over time and make predictions.

Locations

In the SPD's CompStat data, locations of sexual assault offenses are not included in order to protect the victim's privacy. While we know how many sexual assaults are reported and the general policing district that they occurred, it's not possible to correlate that type of assault with specific locations.

When locations are included for other offenses, they are sometimes documented only as an intersection of two roads, with no street numbers or direction. If an address is included in CompStat data, the street number is rounded - a robbery at "1215 E. Main Street" may become "1200 E. Main Street". Sometimes low-numbered locations are documented as "0 E. Main Street". This makes density or "heat" mapping difficult, and the resulting graphics unreliable.

Legal Nuance

There are some distinctions made in the data provided by SPD, and these reflect the definition of certain offenses in the state of Washington. For example, while purse snatching is robbery in that property is being taken from somebody in-person, it's not the same as being robbed at gunpoint or carjacked. Ideally the perpetrator grabs the purse and flees, without brandishing a weapon or harming the victim otherwise.

In the raw data, there are a number of offenses listed as "ROBBERY 2D PERSON (NOT PURSE SNATCHING)". So while the victim's purse was taken in-person and they were "robbed", we won't see it listed as a robbery. This is not so much a shortcoming of the data as it's a nuanced legal distinction. Spokane Police don't categorize offenses, e.g. violent and non-violent, in CompStat reports, so we're left to do that ourselves.

Missing Data

We're missing some data not due to legal details, but because many crimes go unreported. This occurs for a number of reasons depending on the community - social pressures, past negative encounters with law enforcement, prior criminal history of potential reporters, etc. It would be naive to think that all crime committed in Spokane is reported and subsequently documented in the CompStat reports. Assumptions about the percentage of crimes that go unreported depend on complex, interconnected variables that change over time. It'd take a background in statistics, sociology, and criminal justice that I just don't have to develop solid conclusions. For that reason, this project only focuses on analysis and reporting with the data at-hand, without making assumptions about unreported crimes.

Reporting Changes

Spokane's reporting of crime data has also undergone multiple transformations in the last decade. CompStat data is available on the SpokaneCity.org portal from 2019 all the way back to 2015. On October 4, 2016 the SPD moved from one crime reporting standard (UCR) to another (NIBRS). Current CompStat reports state on the first page about the switchover date,

Numbers on CompStat reports prior to this date should not be used as a comparison to those on this report.

Unfortunately, we're not able to make true "apples-to-apples" comparisons across the full timespan of availalble CompStat crime data. Some years also have missing weeks of reports, and it's unclear if that data will ever be available.

Violence and Crime Classifications

In some of the analysis I've made distinctions between violent and non-violent crimes. For the purposes of this project, violent crimes include assault, drive-by shooting, homicide, robbery, rape, and murder. While this isn't an exhaustive list of all possible violent crime on the books in our state, it fits the data provided by SPD. Each week when new data is processed I verify that offenses are parsed and categorized properly. If additional types of violent crime are committed and reported in the data I'll add them to the list and they'll become part of the classification process.

Contact

Thanks for your interest in the project. If you have questions, comments, or press inquiries feel free to email tyler[at]manitonetworks.com.

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Analysis of crime data in Spokane, WA

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