Research Design Education and Crime M5 A3
The study by Sherman et al (1998 ) Preventing Crime : What Works , What Doesn ‘t , What ‘s Promising ‘ presents evidence that much of the research done on crime and prevention remained untapped by their research . They refer to this as fugitive ‘ research done by such organizations as government bodies and that remained largely unpublished . This poses a threat to the validity of the research , as a large inaccessible body of information leaves major gaps in their research that might have altered the results of the study . It also hurts the possibility of randomization [banner_entry_middle]
. The authors report that a bias exists against publishing reports that contain statistically insignificant differences ‘ Though this might not pose a problem for the validity of the result for which programs do work , the inaccessibility of these research reports affects the validity of the results for the section entitled what does not work (1998 , as many of the unsuccessful programs remain unpublished No control variables were used in this study , because it mainly reviewed the literature published in previous studies . However , it strongly considered the control variables of the studies it reviewed in to determine the validity of including their material in the research
The major threat to the study Long-term Effects of an Early Childhood Intervention on Educational Achievement and Juvenile Arrest : A 15-Year Follow-up of Low-Income Children in Public Schools ‘ done by Reynolds et al (2001 ) is its reported lack of randomization . The community chosen for intervention was selected because of its reported high drop-out level . Therefore , although the sample size was very large (n 989 , the subjects were not selected randomly , and this usually poses a validity threat . However , a control group was established for this study , which was also very large , numbering 550 participants . Randomization took place for the controls in that their schools (not the participants themselves ) were selected randomly . In to gauge the actual effects of the intervention (which occurred in the form of the Chicago Child-Parent Program for kindergartens , the control group was chosen as group of pre-school and kindergarten students involved in the regular all-day school programs of their district . The five schools for the control group were randomly selected from the Chicago area . Also because the CPC intervention provides pre-school care , 176 of the 550 control group participants were chosen because of their lack of pre-school intervention
The design of the Sheley et al (1991 ) study , Firearms , violence , and youth in California , Illinois , Louisiana , and New Jersey , 1991 contained favorable and unfavorable aspects for the purposes of validity . It contained a very large sample size , while its breadth spanned several states and included both pre-criminal activity and post-criminal activity youths . However , the nature of the study dictated that the subjects were chosen from a pre-selected group , which did not favor randomization . In to circumvent the effects of this , the authors included as many of the youths in the study as possible However , other possible threats to validity exist . The questionnaires given to the youths were self-administered… [banner_entry_footer]
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