Final answer:
The most common reason why crime prevention strategies have not been as successful as expected is the lack of community participation.
Step-by-step explanation:
The most common reason why crime prevention strategies have not been as successful as the police and public might have hoped is lack of community participation.
According to social disorganization theory, crime is most likely to occur in a community where neighbors don't know each other very well. In such neighborhoods, residents are unable to exert effective, collective social control, making it difficult to prevent crime.
Efforts like building ties and trust with communities through community-oriented policing, neighborhood watch programs, and improvements in street lighting can be effective in reducing crime, but they require active participation from community members.