A colleague of mine just enlightened me with DATA to help substantiate that blogging helps raise test scores:
“Our district is in the middle of a small blogging research project. Preliminary results are that our bloggers have a higher submission rate (80% vs. 69%) and scores (3.38 vs. 3.12 out of 5) on their homework assignments than do those students completing the work on paper. Additionally, their test scores (80.8% vs. 76.6%) for the first unit in the study were higher as well. Thank goodness for Excel or I might not have a way to argue for keeping our blogging feature. We’re in the middle of the next unit, so I’ll keep you all posted to see if the bloggers continue to outscore and outsubmit the nonbloggers.”
For privacy concerns, I will not reveal the source, nor the district, but this is GOOD NEWS! 
I wonder if these stats are saying: “Students with a computer at home, internet access, and enough experience with both to embrace blogging tend to do better at school.” Or if the blogging is done in school, are the teachers self-selecting?
I’m all for providing as many of the best tools as possible for teachers and students, but I have to challenge conclusions from such basic data. I want those tools to be supported by the best, most irrefutable data possible when they are presented / discussed / defended.
You may challenge – there is nothing wrong with that. It is basic data, and I’ll be interested in hearing about the long term gains (or not) when they come in. But we have to start somewhere.
I also must challenge someone not willing to put their name on such a comment – it’s easy to anonymously discount something. Perhaps you’ll consider it next time?
Here is an answer to your comments from the source:
Admittedly, our study is small and these results are preliminary. We have attempted to use these numbers to validate the student engagement teachers felt was heightened by the blogging your homework option. The blog feature was an additional cost, and we wanted to see if there was return on the district’s investment. All of the students in the Spanish II classes except one stated that they had a computer and Internet access in their homes. The blogging is only done at school if students experience a problem with their service at home. We have many labs and students are able to complete their blog postings during homeroom or study hall if this is better for them. Class time is not used for postings. If anyone has irrefutable data on blogging, please submit the information to the blog. As we could not find such data, we felt we needed to gather information on our own students to see if this is money well spent or if we should consider other tools which might be better for our students.