Rates of inappropriate laboratory testing, 1997-2012.

<p>Subgroup Summary Statistics.</p>a<p><i>P</i> for stratum differences is meaningful only when there is a natural ordering for categories. <i>P</i> for difference of means: chemistry vs. hematology, <i>P</i> = 0.05; chemistry vs. microbiology, <i>P</i> = 0.65; chemistry vs. molecular, <i>P</i> = 0.17; hematology vs. microbiology, <i>P</i> = 0.43; hematology vs. molecular, <i>P</i> = 0.07; microbiology vs. molecular, <i>P</i> = 0.19.