Inconsistency in root structure could throw off results.

Since we're designing a bulletproof test for this all-important question, the obvious answer would be to recruit about a dozen volunteers who would each dig a hundred holes to a uniform depth using each trowel, carefully recording the time required and grading such variables as ease of use on a 1 - 10 scale, corresponding to the best available indictors. These could be charted on a scatter graph, noting how they clustered.

Anyway, I'm sure the more experienced post-grad MS and PhD degrees among us could power their way past these small difficulties in study design and statistical interpretation. Then we'll have real information, not just a bunch of random data. laugh