Is it possible to establish a consistent, stable relationship between the structure of number and additive amounts of mindfulness practice? A bank of thirty items, constructed from a review of the literature and from novice practitioners' journal responses to mindfulness practice, comprised the instrument. A convenience sample of students in a teacher education program participated. The WINSTEPS Rasch measurement software was used for all analyses. Measurement separation reliability was 0.92 and item separation reliability was 0.98, with satisfactory model fit. The 30 items measure a single construct of mindfulness practice. Construct validity was supported by the meaningfulness of the items perceived as easy to hard. The same scale was produced when the items were calibrated separately on the T1 and T2 groups (Rsq = 0.83). The experimental group's T2 measures were significantly different from both its own T1 measures and the control group's T1 and T2 measures. ANOVA showed significance for variance between the experimental and control groups for T2 (F = 43.66, 151 d.f., p < .001) for a nearly two-logit (20 unit) difference (48.9 vs. 68.0). The study is innovative in its demonstration of mindfulness practice as a measurable variable.