An oldy but goodie from Will Thalheimer, since Benchmark Learning apparently didn't know it when they used bad recall data in their whitepaper -
The Future of E-Learning: Understanding the ROI Benefits of Modern Corporate Training Tools
"People do NOT remember 10% of what they read, 20% of what they see, 30% of what they hear, etc. That information, and similar pronouncements are fraudulent. Moreover, general statements on the effectiveness of learning methods are not credible---learning results depend on too many variables to enable such precision. Unfortunately, this bogus information has been floating around our field for decades, crafted by many different authors and presented in many different configurations, including bastardizations of Dale's Cone. The rest of this article offers more detail. ..."