2022-08-02

Introduction

  • Belief in a “lunar effect” traced to ancient times
  • People more aggressive & impulsive when moon is full
  • Led to belief that crime rates rise during full moons
  • Put it to the test with real world data
  • Altanta Crimes, 2009-2017
  • Lunar Phases,1900-2022
  • Data sourced from Data.World

The Data

Crime in Atlanta
crime number date location beat neighborhood npu lat long
LARCENY-NON VEHICLE 103040029 10/31/2010 610 SPRING ST NW 509 Downtown M 33.77101 -84.38895
AUTO THEFT 103040061 10/31/2010 850 OAK ST SW 401 West End T 33.74057 -84.41680
LARCENY-FROM VEHICLE 103040169 10/31/2010 1344 METROPOLITAN PKWY SW 301 Capitol View Manor X 33.71803 -84.40774
AUTO THEFT 103040174 10/31/2010 1752 PRYOR RD SW 307 Betmar LaVilla Y 33.70731 -84.39674
LARCENY-NON VEHICLE 103040301 10/31/2010 JOHN WESLEY DOBBS AVE NE / CORLEY ST NE 604 Old Fourth Ward M 33.75947 -84.36626

Lunar Cycles
…1 new moons first quarter moons full moons third quarter moons
1 1900-01-01 1900-01-07 1900-01-15 1900-01-23
2 1900-01-30 1900-02-06 1900-02-14 1900-02-22
3 1900-03-01 1900-03-07 1900-03-16 1900-03-23
4 1900-03-30 1900-04-06 1900-04-14 1900-04-22
5 1900-04-28 1900-05-06 1900-05-14 1900-05-21

Data Transformation

## Group by date and total type of crime per date
bydate <- crime %>%
        group_by(date,crime) %>%
        tally(name="totalReported")

bydate <- as.data.frame(bydate)
## Group by date totaling all crime for each day
bydate <- bydate %>%
        group_by(date) %>%
        summarise(totalReported=sum(totalReported))
## Create dataframe that only has dates of the full moon
fullMoon <- select(moonPhases, date = "full moons")

## Change date formats so they match
bydate$date <- mdy(bydate$date)
fullMoon$date <- as.Date(fullMoon$date, format= "%m/%d/%Y")
## Create variable that indicates if moon is full on each date
bydate <- bydate %>%
        mutate(full = case_when(date %in% fullMoon$date ~ "yes",
                                          TRUE          ~ "no")
        )

The Transformed Data

Crime in Atlanta
date totalReported full
2009-01-01 114 no
2010-01-01 92 no
2011-01-01 104 no
2012-01-01 75 no
2013-01-01 91 no

Crime Rates and the Full Moon

Summary

  • No major rise in crime rates on days with a full moon
  • Therefore, the full moon has no affect on crime rates
  • Limitations: Data limited to violent crimes in Atlanta,GA from 2009-2017.