posted on Nov, 5 2012 @ 06:31 AM
reply to post by elouina
Stratified sampling is quite common when polling. Stratification looks like oversampling, but it is planned and the effect of the stratification can,
and should, be removed when reporting the results. The reason this is done is to get more precise information on key, small subgroups within the
population being sampled. What makes them "key" is that they might be of special interest or the client who paid for a poll may have asked for more
information about specific subgroups.
You would have to get into the details of the analysis to determine if the reporting of the results was biased due to uncorrected stratification. That
type of information is rarely reported by the media -- very few people would understand it. Actually, most people have difficulty seeing how a sample
of 1100 people couple possibly represent the opinions of the entire country. The truth is, samples (even small ones) are frequently much more
accurate than a census (asking everyone).
Anyway, if there was stratification and the raw results were reported, the impression provided to the reader would be biased. I haven't gone over
the details of this particular poll, so I can't speak about it directly. I will say though that it is possible that a reputable polling organization
could be pressured into reporting raw results through the threat of lawsuits. It's also possible, but very unliekly for a reputable firm, that they
may simply want to assist a particular candidate by making him/her look better than they are. It has certainly been claimed that some, possibly all,
major media are both manufactuirng and skewing news at the request of specific governments and political parties / politicians. In this particular
poll? Who knows!
Reporting raw results only even when stratification corrected results are available would be a skewing of the news that might appear defendible to
many people not familiar with statistical methods.