Growing With Grammar is a fantastic grammar program. The author, Tamela Davis, started with a third-grade level and has just completed her fourth-grade level.
I have not seen the fourth-grade level, but my son worked through GWG3, so I'm positive that it is as fantastic as 3.
I like to compare GWG to Rod and Staff. Rod and Staff is a great program, although it's time consuming and writing all those sentences out by hand is excruciating. Also it is very religious. Growing With Grammar is to the point and very well laid out. Anyone of any faith or lack thereof can use this program without any hesitation. GWG's coverage is "just the right amount" whereas Rod and Staff tended to go on and on and on. Also, with Rod and Staff, we have to do grammar 4 days a week in order to complete the book in a year. GWG covers the same ground but it can be done fewer times a week and be finished in the year.
I just read on the GWG website that the author is going to write a 1st/2nd grade combo program and will also be working on her 5th grade program, both due out in spring of 2007.
My son was behind on his grammar skills, according to his 3rd grade CAT5 results. We did GWG3 in 4th grade and his English test scores on his 4th grade CAT5 went way up. (Yes, they were above grade level.) That, IMHO, is proof that it is a good program. I really do believe that her program helped give Thomas the boost that he needed.
Growing With Grammar