Also ... Massachusetts MCAS scores are often an indicator of academic achievement in the towns. http://www.doe.mass.edu/mcas/results.html
However, the definition of "good" is very subjective and while seeing the statistics about school districts is informative and contributes to one's evaluation of a school and perhaps in helping to narrow down which school districts to consider ... I would ulimately recommend a visit to the school once you have narrowed down to two or three schools.
Looking at the local paper often gives a flavor of the community as well, which would factor into the educational experience for children.
Walpole is covered by http://www.walpole.org/ and http://www.wickedlocal.com/walpole and http://www.thesunchronicle.com/
Norwood is covered by http://norwood.patch.com , http://www.wickedlocal.com/norwood and http://www.allyoucanread.com/norwood-newspaper-ma/
Best of luck and let me know if I can be of any assistance! I grew up in the South Shore and spent many years competing in the Hockamock League (Go Bulldogs!) :-)