A recent VICE interview with professor of criminology, Dr. Janet Lauritsen and an Oxygen interview with Dr. Sherry Hamby, the founding editor of the Psychological Association journal Psychology of violence, shed some light on this question.
Lauritsen sees an increase in two kinds of crime over the holidays: robbery and personal larceny. She believes this increase in holiday crimes has more to do with opportunity than desperation. There are a lot of people out shopping for expensive goods, making shopping bags and cars full of gifts tempting targets. Criminals also benefit from increased traffic as it makes it easier for them to blend in and escape after committing a crime.
According to Hamby, "Crimes spike on days off-- so, all year round, crime rates are much higher on Friday and Saturday and is higher at night than in the morning. So any increase during the holidays might be simply due to more idle time and more drinking and other drug use."
The best way to avoid becoming a victim of holiday crime is to remain alert to your surroundings. Make sure your car is always locked while shopping. Try not to carry so many bags you are unable to defend yourself in the case of an attack.