There were two issues. She talks about the different techniques of pre drafting versus splitting/ stripping, yet in her experiment, she plied one with a white yarn and plied the other with itself. I really couldn't tell the difference, and the fact that she therefore had 2 variables bothered me.
I took this roving and split it, plying it with itself:
And the result:
Then I took this roving and pre drafted it and plyed it with itself:
I couldn't tell any difference between the two techniques.
So I decided to run an experiment of my own. I dyed up some roving with koolaid in my crock pot (lemonade, black cherry, and iced blue lemonade) ( I think).
The resulting roving looked surprisingly like a snow cone.
The pre drafted roving (top) had a much greater chance of multi colored singles. The stripped roving is a little more vibrant. In both of these, I divided the roving in half, spun on different bobbins, and then plied together. There wasn't a large degree of matching up. I still can't tell much of a difference between the two.