Purpose is a mental idea. I can tell you my purpose for something and it will be logical. A need is emotional and drives you.
"The purpose of me following this diet is to lose fat, gain muscle and live a long and healthy life."
"Oh, my god, I NEED that pizza!!!!!!!!!"
That's the difference. Which is going to win. The answer is whichever is stronger but I guarantee you that if the purpose of the diet wins it's because it was translated into a feeling that was stronger than the need for the food.
The PR course covers purpose but it never mentions need or emotions or feelings. If you think that they ARE covered under the word "Purpose" then there you go, I'm wrong.
This is all just my opinion and it's what works for me. Personally, I don't preview, gather trigger words, do mind maps or any of that stuff.
I pick up a book and scan it. How do I feel about this book? How do I feel about the author? Should I spend time with this book or look for another one? If I get that positive feeling, like a warm feeling, I PR it, then superread and dip and I'm all done.
I should honestly shut up about this because the reason I come to this forum is to brush up on QiGong.
PR does work and if you can't get it to work, it's still faster than any method out there. PR at 10% is even better than everything else at 100%. Just keep going. There's no point in quiting. Quiters are losers. You already did the work, you bought the course or book, you know it. Maybe you're just too picky about what a result is. Maybe you're so identified with getting something to "work" that you forgot why you were reading in the first place.
Last year I took a break from all the "superachiever" stuff and thanks to (a sale at) Learning Strategies finally bit the bullet and got the QiGong course by Chunyi Lin and it was exactly the break that I needed. I've been playing with Lifeforce ever since and am not really even interested in books so much anymore. I've been playing with this energy everyday and now when I go back to trying to photoread my old way I just laugh because I'm much faster at it. Lin teaches to "call upon the masters energy" and now I do that with the books and it's like ten times easier.
Alex said "If you've ever flunked on a test even though you've read the book. You lacked a purpose for reading." I think this has more to do with blocked energy than anything else. If you've read the book then you've GOT it, whether you read it consciously or with the PR step. Just my opinion though.