"Does the preventive action work?"

Another determinant is whether or not the person believes that the preventive action actually works (i.e., if it can indeed prevent the disease or problem). Another name for this barrier is "perceived action efficacy." If people think the preventive action you are promoting does not work to prevent the problem or disease, then they probably will probably not do it.

Examples

• The old fisherman did not quit smoking because he thought that stopping smoking (at his ripe old age) would not help prevent cancer.

• Let's say that a mother thinks that her child can get dehydrated (1), and that dehydration is very serious (2), but that ORS does nothing to correct dehydration (i.e., that ORS is not efficacious at preventing dehydration).
  
  Will she use it? Probably not. The same can be said for men who think that fidelity in marriage will not help them prevent AIDS. Another example would be a man who chooses to sleep with multiple partners who says - by some very strange logic - that if he cannot be 100% sure he is preventing AIDS by wearing a condom, then he will never use one.

• Let's say that a farmer believes that his grain in storage could get bugs in it (1), and that situation would be very serious (2), but that the smoke from a fire built under his improved silo will not keep the bugs out. In that case, he may not build an improved silo.

How could you convince a person that an improved silo works? Or that ORS works?

First, we could use questions to find out why he/she thinks that it does not work. You could then invite a farmer to talk to another farmer, or a mother to talk to another mother, who has used the practice and believes it works.

This determinant can also be turned around into a positive attribute of the action. If someone believes that a particular behavior is highly effective, you can ask them why they think it works and use their response (assuming it’s true) when promoting the behavior with others.