Clara examines the number of traumatic head injuries that occurred in California for five years before and after the passage of a law that made it mandatory for riders to wear a helmet. Clara's research design would be classified as a(n) :

A) nonequivalent control group pretest-posttest design.
B) nonequivalent control group design.
C) control series design.
D) interrupted time series design.

Interrupted Time Series Design

A quasi-experimental research design that examines the effects of an intervention by analyzing data collected at multiple points before and after the intervention is implemented.

Traumatic Head Injuries

Physical injuries to the head that may result in impairment or damage to the brain.

Mandatory Helmet

A rule or law requiring individuals to wear helmets while engaging in certain activities, such as cycling or motorbiking, to reduce the risk of head injuries.