We have long accepted the concept of "cause and effect"; do one thing and something else will occur. Sometimes the result of a cause is a surprise, such as the side effects of some medicine. Other times, we take a specific action (the cause) to create a specific result (the effect). Often the cause is controllable and, if the result is favorable, we continue; if not, we cease. Such relationships are often of considerable interest to law enforcement and we measure one factor (a cause) in order to determine another (the result). We might count the number of neighborhood watch programs operating and assume that the more programs we have in effect, the less burglaries we will have. We might expect that the number of assaults in a parking lot would decrease if lighting were improved. Or we might look to another community's changes in crime after a particular action has been taken, such as the building of a regional shopping center .