Two cents

I'm really sorry for the 6 week gap, I had to be hospitalized with typhus for eating ham, pepperoni and what I thought was spring water. (I'd rather not discuss the latter)Now everyday we come across surveys whether on our Kellog's cereal box [I think these people who agree to eat cereal in the middle of the day can do anything] or on our non nonaddictive pain reliever "Catniz zipzap 632" more effective in a trial on 33% Norwegians than swedes [except for the occasional Demerol].
Here's another angle, see that those warnings have got larger that tobacco causes cancer? So from 1900 to 2000 the lung cancer incidence has increased exponentially as has the sale of cigarettes- No, THIS DOES NOT PROVE TOBACCO CAUSES CANCER, THE SALE OF POTATOES HAS INCREASED EXPONENTIALLY TOO!
Finally I heard my psychology graduates did this survey- they called 100 people and asked if they wanted to buy a music player- all said NO THEY ALREADY HAVE ONE - so does every one in the city with slums have? No BUT IF THEY WERE RICH ENOUGH TO OWN A PHONE/ANSWERING MACHINE its likely they ALSO HAVE a tape recorder.
FINALLY I SAY YES THEY ARE USEFUL BUT IT'S VERY DIFFICULT AND RIGID TO DO ONE CORRECTLY ,MAY BE THAT'S WHY AFTER A DRUG IS DISCOVERED IT TAKES 10 YEARS TO COME TO THE MARKET.