those #'s are completely dependent on what study you look at, what climate, what timing, rate, etc. I spent about 10 minutes and found about 10different studies involving crabgrass control with prodiamine or dimension. In some, prodiamine performed better, in some, dimension performed better. Here, unless you are splitting applications, and no one in my area does, the life of prodiamine is much longer. therefore, it is a far better product in my area and in my opinion.