Skip to main content

Table 2 Regression to the mean effects for Physical Component Summary (PCS) scores on the Short Form-12 (SF-12v2), from the high-risk (PCS values ≤ 44.25) subgroup of controls ( n = 34) participating in a health coaching study (Butterworth et al. 2006)

From: Assessing regression to the mean effects in health care initiatives

Variable Mean Std. error [95% Confidence Interval]
Actual     
Pre-test 36.65 2.21 32.32 40.97
Post-test 44.93 3.27 38.51 51.34
RTM 8.28 2.01 4.35 12.21
Calculated     
Pre-test 40.02 0.78 38.49 41.56
Post-test 43.41 1.52 40.44 46.38
RTM 3.38 0.94 1.54 5.22
Difference (Actual – Calculated)   
Pre-test −3.38 0.83 −5.01 −1.74
Post-test 1.52 1.82 −2.04 5.09
RTM 4.90 1.93 1.12 8.68
  1. Notes: “Actual” indicates that the pre-test, post-test and RTM effects were estimated directly from the data. “Calculated” indicates that Equations 1, 5 and 6 were applied directly to the existing data. Standard errors and 95% confidence intervals were derived by bootstrap resampling of the data 1000 times.
\