University yield trials are an excellent source of information, but they can only provide general information.  They may not include varieties of interest to you.  Additionally,  they are only conducted in a limited number of locations.  In recent years, many universities have reduced or eliminated their variety trials.

Because the university yield trials are useful, CropFax uses statistical analysis combining the information from more than 40 universities plus trials from county tests and commercial test plots.  Each year CropFax collects about 225,000 field trial results compared to about 700 results in a typical university trial. 

More comparisons from more locations mean better information for you, the grower.