An example of causal research would be a restaurant wanting to find out why fewer customers were demanding one of its sandwiches, so management might experiment to find out if possibly the sandwich's current price or a new competitor's presence in the area would be a cause. The purpose of such research is to find out what is causing a specific change, and in business, this might be a decline in sales.
Causal research can help businesses determine how changes they make will affect operations, so it's helpful for planning. Other fields such as science and economics also use this kind of research, and experimentation and statistical research may be performed to determine the cause and effect of an issue. Laboratory experiments and field experiments both are common.