The Stats on Animal Abuse
Feb 10, 2010
By Matt Bogard
In a recent article, animal rights activists (Mercy for Animals-MFA) went undercover and made some observations about animal abuse on dairy farms. See-
Governor Paterson, Shut This Dairy Down
The author of the above article states:
"But the grisly footage that every farm randomly chosen for investigation--MFA has investigated 11--seems to yield, indicates the violence is not isolated, not coincidental, but agribusiness-as-usual."
This is exactly why economists and scientists employ statistical methods. Anyone can make outrageous claims, but are these claims really consistent with evidence? If we take a sample from a population, the fact that the sample was 'random' doesn't necessarily make our conclusions about the population it came from valid. Random sampling might be necessary, but it's not sufficeint.
Before we can say anything about the population, we need to know 'how rare is this sample? Was it observed just by chance or does it represent what’s really going on in the population? According to the USDA, in 2006 there were 75,000 dairy operations in the U.S. According to the activists claims, they 'randomly' sampled 11 dairies and found abuse on all of them. That represents just .0146% of all dairies.
If we wanted to use sample data to estimate the proportion of dairy farms that were abusing animals, if we wanted to be 90% confident and be within a margin of error of .05, then basic statistics dictates that the sample size required to estimate this proportion would have to be about 271 farms!
I'm sure the article that I'm referring to above was never intended to be scientific, but the author should have chosen their words more carefully. What they have is allegedly a 'random' observation and nothing more. They have no 'empirical' evidence to infer from their 'random' samples that these abuses are 'agribusiness-as-usual' for the whole population of dairy farmers. While MFA may have evidence sufficient for taking action against these individual dairies, the standard should be set much higher in order to support a larger role for government in animal agriculture, which seems to be the goal of many activist organizations.
Profits, Costs, and the Changing Structure of Dairy Farming / ERR-47
Economic Research Service/USDA Link
"Governor Patterson Shut Down This Dairy", Jan 27,2010. OpEdNews.com