This model depicts the complex relationships between crime, number
of police, investment in community development programs and the youth
population of the small country town, Bourke.
In this system dynamics model, the user can observe how modifying
the spending on community development programs and changing the number of
police in the town affects the crime rate and the engagement of youth.
These
variables can be altered using the sliders which are provided underneath the notes. The
model runs for a period of 5 years. This was deemed the optimal time during
which any generational changes could be observed.
The model is explained with more detail below, along with any
assumptions and their appropriate reasoning.
Variables
Investment in
Community Development Programs
It is assumed that the minimum that can be
invested is $1000 and the maximum is $100 000.
Number of Police
It is assumed that the minimum number of
police officers that can be present in Bourke is 10 and the maximum is 100.
Stocks and Flows
Bourke
Population
The population
of Bourke is set as 3000 as stated in the Justice Reinvestment document.
Boredom and
lack of opportunity leads to
This flow is
given the equation: (50000/[Investment in Community Development Programs])* 2. The greater the investment in community development programs, the lesser the number of youths who are bored.
Disengaged and
Alienated Youth
Since there
are not many activities for young adults (as stated in the Justice Reinvestment
document), it is assumed that they are all currently disengaged and alienated.
The disengaged and alienated youth population of Bourke is thus set as 1000
before the model is run.
Petty Crime
Since the youth
crime rate for Bourke is quite high, it was assumed that 800 out of the 1000
youth would engage in petty crime. This is before any additions to the police
force or increase in community development programs investment.
Commit
This flow is dependent on both the number of disengaged youth and the number of
police. The more police that are present in Bourke, the more disengaged the
youth become. This ensures that the level of petty crime committed is directly
related to the number of police officers.
Convicted
This flow is given a constant rate of 7*[Number of Police] + (0.1*[Petty Crime]).
This means that the greater the number of police officers present, the greater
the number of convictions. It also means that at the highest number of police
officers available (100), the highest the number of convictions is 700 + 10% of
youths who commit a crime. Since the model assumes that there are 800 youths committing
crime at the beginning of the models’ commencement, it realistically represents
the police’s inability to catch ALL criminals.
Not Convicted
This flow has the equation ([Petty
Crime]/[Number of Police])*2. Since the number of police is in the denominator,
the lower the number, the higher the number of delinquents who are not
convicted. This attempts to keep the model realistic. At the maximum level of
100 police officers, there will still remain some delinquents who escape
conviction and this remains true to life.
Lesson Learnt
Since youth
crime is so rife in Bourke, it is assumed that only 20% of offenders in the
juvenile detention centre learn their lesson and never commit crime again. This
was done to simplify the modelling.
Still
Disenchanted
It is assumed
that 80% of offenders do not learn their lesson after their time in the
juvenile detention centre.
Feel Estranged
This flow is given the equation: [Number of Police]*5 + 50/([Investment
in Community Development Programs]/1000).
Thus, the higher
the number of police, the greater the number of youths who feel estranged. The
greater the investment in community development programs, the lesser the number
of youths who feel estranged.
Participate
and engage in
This flow is
dependent on the level of investment in community development programs. The
greater the investment, the greater the participation. This is realistic as the
more money is spent on such programs, the more interested that youths will be in participating.
Develop
Inter-community relationships
It is
estimated that the majority of youths who participate in community development programs
will develop inter-community relationships. This model assumes that such
programs will be largely successful in encouraging social harmony amongst the
youths.
Relapse
However, youths
participating in the community development programs may relapse and head back
into the path of crime. However, this is assumed to only be a small minority (1/8
of those who participate).
Interesting
Observations
1) Number of
Police: 10 (minimum)
Investment in
Community Development Programs: $1000 (minimum)
It is
important to note that even the minimal amount of investment in community
development programs is enough to cause the crime rate to decrease, to the
point where, after 3 years, there are
more youths who are Reformed and Engaged than those involved in Petty Crime.
However, the number of youths who are Reformed decreases after some time,
indicating greater investment is needed. Somewhat surprisingly, the number of youths who are involved in the
community development programs is at its highest, further suggesting the need
for increased investment.
2) Number of
Police: 100 (maximum)
Investment in
Community Development Programs: $1000 (minimum)
Predictably,
Petty Crime has drastically decreased, and in a much shorter time than when
there were only 10 police officers. The number of youths who are Reformed and
Engaged and those who are involved in the Community Development Programs has also
increased, but they are not as high as in the previous observation, most likely due
to increased alienation caused by the high police presence.
3) Number of
Police: 10 (minimum)
Investment in
Community Development Programs: $100 000(maximum)
Quite
surprisingly, Petty Crime has decreased drastically, despite the low number
of police officers present in Bourke. This shows that the large sums of money
being invested in the Community Development Programs has created a social change within the town’s youth population with high numbers of
youths participating in these programs and thus becoming Reformed and Engaged. Another
interesting aspect is that while the number of youths participating in the programs reduces to
zero at the end of the fifth year, the number of youths who are Reformed and Engaged is at an all time high.
4) Number of
Police: 100 (maximum)
Investment in
Community Development Programs: $100 000 (maximum)
While Petty Crime has decreased significantly, the number of youths who are Reformed and Engaged and those who participate in Community Development Programs is not as
high as Scenario 3. Extremely large numbers of youths are also spending time in
the Juvenile Detention Centre during the first 2 years of the 5-year model. While repeat offences
are low, this may be more due to fear of police brutality and the prospects of
harsher sentences than any conscious effort on the youth population’s part to
be more harmonious members of society.
