iPad and Kindle Reading Speeds (Jakob Nielsen's Alertbox)
The iPad measured at 6.2% lower reading speed than the printed book, whereas the Kindle measured at 10.7% slower than print. However, the difference between the two devices was not statistically significant because of the data's fairly high variability.Thus, the only fair conclusion is that we can't say for sure which device offers the fastest reading speed. In any case, the difference would be so small that it wouldn't be a reason to buy one over the other.
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Nielsen researches readability on Kindle and iPad. I expected that Kindle will score higher with its e-paper technology.