Shortly after the first case of Bovine Spongiform Encephalopathy (BSE or mad cow disease) was discovered in the U.S. in December 2003, a Kansas State University survey asked consumers how the news had affected their beef consumption habits. Seventy-seven percent said their consumption had not changed. Of those whose consumption had changed, the respondents reported they were consuming less ground beef, hot dogs and steaks.
As things turned out, the market data showed that for the first quarter of 2004, just after the discovery of the first U.S. BSE case, there was no weakening of domestic beef demand. Sean Fox, the KSU agricultural economics researcher who conducted the survey for the Food Safety Consortium, wasnt surprised.
The discrepancy between actual market behavior and survey data may be partly a result of non-response bias, with those who felt most strongly about the issue being more likely to reply, Fox said, or hypothetical bias in the responses themselves, with individuals responding in the way they felt they ought to and thereby indicating that their consumption had fallen.
Or, Fox said, the respondents may have actually reduced their consumption of certain been products, but only for a short time and not long enough to be reflected in market data.
Every time you do a survey you face that kind of bias in the responses, Fox explained. Thats the reason we find it so hard to predict what would happen if we had another case.
In early 2004, Fox also asked respondents how they would react if a second BSE case were discovered. They appeared to be less tolerant of BSE the second time around: 44 percent said they would reduce their beef consumption.
But once again, the respondents may not have put their professed intentions into practice at the marketplace. A second BSE case in the U.S. was confirmed in June 2005. As in the first case, meat from the affected cow did not enter the food supply. And also as in the first case, domestic beef demand did not suffer.
If repeated multiple cases of BSE were found in the U.S., the survey suggests that there would be major trouble for the beef industry. Surveyors asked what consumers would do if 20 cases of BSE were discovered, but the responses varied according to how the question was framed.
When asked only if 20 cases were found, 43 percent said their consumption of beef would fall and another 26 percent said they would stop consuming any beef. But among people who were asked two questions together one asking their reaction in the event of one BSE case and the next question asking their reaction to 20 cases 39 percent said their beef consumption would decrease and 45 percent said they would cut out beef completely.
These results show how responses depend on how the question is framed, Fox said. Its still very difficult to predict exactly what would happen if we do have multiple cases. The best we can do is put out accurate information about the fact that the risk to consumers is incredibly low.
Source: Kansas State University