I would venture the numbers are something like this:
$50m gets you 500,000 Kindle equivalents, which maybe gets you 12 months of reading say, for 2 kids, until it burns out (my wife's lasted 18 months with lite usage in the ideal climate of San Jose!). So 1 million kids read for a year.
Alternatively, $50m gets you 2000 libraries with 4 years of library service for, say, 200 kids. Assuming each library costs $15,000 to get started and then costs $2,500 per year for 4 years, so $25,000 per library. So $50m gets you 2000x200= 400,000 kids read for 4 years or 1.6 million kid/years.
So the two are pretty comparable. Why is all the attention on distributing e-readers rather than extending the pathetically low numbers of community libraries (Burkina has at most 20 village libraries for maybe 5,000 villages that ought to have libraries. Uganda has a 100 in Uganda Community Library Association, for a population that is almost double the population of Burkina.)
Then we start thinking of intangibles. E-readers generate demand for recharging and... nothing else. I doubt there will be much of a market for repairing e-readers. Libraries generate demand for... carpenters, authors, publishers, newspapers, librarians, summer reading camp counsellors, good governance, etc etc. I'd love to see e-readers subject to a proper test... distribute $50m in Kindles, and spend $50m on an NGO (hmmm... FAVL?) library program.
Anyway, what prompted this is this blog entry from Berk Ozler at the World Bank. Child laptops had very few effects in any case....
A few months ago, the first randomized evaluation of the One Laptop Per Child (OLPC) came out as a working paper (you can find a brief summary by the authors here), after circulating in the seminar/conference circuit for a while. Many articles and blogs followed (see a good one here by Michael Trucano and find the short piece in the Economist and the responses it generated from OLPC in the comments section) because the study found no effects of OLPC in Peru on test scores in reading and math, no improvements in enrollment or attendance, no change in time spent on homework or motivation, but some improvements in cognitive ability as measured by Raven's Progressive Colored Matrices.At the Australasian Development Economics Conference (ADEW) I attended last week at Monash University in Melbourne, another paper on a smaller pilot of the OLPC in Nepal presented similar findings: no effects on English or Math test scores for primary school children who were given XO laptops along with their teachers (This study has some problems: the schools in the control group are demonstrably different than the treated schools, so the author uses a difference in difference analysis to get impact estimates. There are worries about mean reversion [Abhijit Banerjee pointed this out during the Q&A] and some strange things happening with untreated grades in treatment schools seeing improvements in test scores, so the findings should be treated with caution). What I want to talk about is not so much the evidence, but the fact that the whole thing looks a mess - both from the viewpoint of the implementers (countries who paid for these laptops) and from that of the OLPC.