Here's a NYT article summarizing the studies:

In a draft of an article that the Quarterly Journal of Economics will publish early next year, the professors report finding "strong evidence that children in households who won a voucher received significantly lower school grades in math, English and Romanian." The principal positive effect on the students was improved computer skills.

At that time, most Romanian households were not yet connected to the Internet. But few children whose families obtained computers said they used the machines for homework. What they were used for — daily — was playing games.

In the United States, Jacob L. Vigdor and Helen F. Ladd, professors of public policy at Duke University, reported similar findings. Their National Bureau of Economic Research working paper, "Scaling the Digital Divide," published last month, looks at the arrival of broadband service in North Carolina between 2000 and 2005 and its effect on middle school test scores during that period. Students posted significantly lower math test scores after the first broadband service provider showed up in their neighborhood, and significantly lower reading scores as well when the number of broadband providers passed four.

The Duke paper reports that the negative effect on test scores was not universal, but was largely confined to lower-income households, in which, the authors hypothesized, parental supervision might be spottier, giving students greater opportunity to use the computer for entertainment unrelated to homework and reducing the amount of time spent studying.

The North Carolina study suggests the disconcerting possibility that home computers and Internet access have such a negative effect only on some groups and end up widening achievement gaps between socioeconomic groups. The expansion of broadband service was associated with a pronounced drop in test scores for black students in both reading and math, but no effect on the math scores and little on the reading scores of other students. In the report, the authors do not speculate about what caused the disparities. Neither author responded to a request for an interview.

The state of Texas recently completed a four-year experiment in "technology immersion." The project spent $20 million in federal money on laptops distributed to 21 middle schools whose students were permitted to take the machines home. Another 21 schools that did not receive funds for laptops were designated as control schools.

At the conclusion, a report prepared by the Texas Center for Educational Research tried to make the case that test scores in some academic subjects improved slightly at participating schools over those of the control schools. But the differences were mixed and included lower scores for writing among the students at schools "immersed" in technology.

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