My name is Bonny and I take potentially perverse delight in reading crappy survey instruments. And like the doorknobs in the Sixth Sense--the mistakes are more obvious when you go back for a second glance.
I am not judging without merit and I never criticize without offering to help. You may have noticed a series of posts about survey design with easy peasy suggestions you can adopt immediately--or ignore. Your call.
The survey instrument is one of the most popular and accessible tools for gathering data. The quality of that data is determined by the questions asked, how they are written, fielded, and analyzed as well as your answer bank and format.
Just the other day a professional society fielded a list of learning objectives claiming that attendees would be able to "appreciate and understand" a list of general PRO measures.
I asked how they would measure both of these behaviors simultaneously or even separately. How does one measure "appreciation" or "understanding"? Is that really the desired outcome?
Whether you use a survey instrument or other metrics to gather information, you need to be precise. Go ahead and open the next survey you are fielded. There are likely multiple lessons for you to discover.
We differ at the nucleotide level somewhere between 1 in 1000 to 1 in 1500--when you consider we differ from chimpanzees at only 1 in 100 this brings some scope and perspective. Looking at the graphic below it seems that we do vary into neat little buckets by race. Until we introduce a population of South Indians that assume a geographic identity somewhere between the 3 measured below (yellow dots in structure analysis graphic).
A neighbor-joining tree is one of several tools to construct phylogenies or evolutionary histories. Maximum likelihood, maximum parsimony and Bayesian Inference are able to not only measure the amount of change between sequences but also specifically identify the differences. But for looking at whole genome phylogenetic tree, you can make a distance matrix based on how many genes differ between your species, and use that to construct an NJ tree.
Genetic variation, classification and 'race"--Jorde and Wooding
The longest branches in this tree separate individuals within the same continental populations (most variation occurs within populations)--branch length refers to how much difference occurs along a branch
The longest internal branch separates African from non-African individuals.
The variant has a frequency as high as 90% in some African populations and as low as 30% in European populations.
I see "data" people...won't you join us?