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. 2020 May 8;29(11):3113–3134. doi: 10.1177/0962280220920669

Table 3.

Applications of the l1-penalized least squares with hierarchical group LASSO variable selection (l1-PLS-HGL), l1-penalized least squares with group LASSO variable selection (l1-PLS-GL), adaptive contrast weighted learning (ACWL), and direct learning (D-learning) to data from male donors in the INTERVAL trial assuming the target is to maximize the utility. The trade-off parameter b in the utility function varies from 1 to 5 at an increment of 1.


Assignment Percentages

ITR Effects
Trade-off Parameter Method 12 weeks 10 weeks 8 weeks Donation Deferral Utility
b = 1 l1-PLS-HGL 0.9 (0.1) 1.2 (0.1) 97.9 (0.1) 1.309 (0.008) 0.024 (0.001) 1.064 (0.009)
l1-PLS-GL 0.3 (0.1) 2.4 (0.8) 97.2 (1.0) 1.289 (0.014) 0.025 (0.001) 1.040 (0.014)
ACWL 0.0 (0.0) 0.0 (0.1) 100.0 (0.1) 1.314 (0.003) 0.027 (0.000) 1.055 (0.002)
D-learning 0.7 (0.2) 1.2 (0.5) 98.1 (0.5) 1.309 (0.012) 0.025 (0.001) 1.058 (0.013)
b = 2 l1-PLS-HGL 3.4 (0.1) 4.2 (0.3) 92.4 (0.4) 1.242 (0.016) 0.021 (0.001) 0.809 (0.020)
l1-PLS-GL 1.7 (0.4) 7.2 (1.6) 91.1 (2.0) 1.217 (0.027) 0.022 (0.002) 0.774 (0.024)
ACWL 2.7 (0.8) 3.4 (1.7) 93.9 (1.3) 1.266 (0.019) 0.022 (0.001) 0.814 (0.016)
D-learning 1.5 (0.4) 5.8 (1.1) 92.7 (1.0) 1.260 (0.022) 0.022 (0.001) 0.816 (0.023)
b = 3 l1-PLS-HGL 8.6 (0.3) 11.9 (0.5) 79.5 (0.6) 1.091 (0.022) 0.011 (0.001) 0.689 (0.028)
l1-PLS-GL 4.8 (1.1) 15.0 (3.3) 80.2 (4.4) 1.069 (0.056) 0.017 (0.003) 0.569 (0.041)
ACWL 9.3 (1.4) 8.2 (2.7) 82.5 (2.2) 1.100 (0.034) 0.014 (0.001) 0.627 (0.032)
D-learning 3.8 (0.8) 17.5 (1.6) 78.6 (1.3) 1.067 (0.027) 0.016 (0.001) 0.607 (0.027)
b = 4 l1-PLS-HGL 17.0 (0.4) 23.3 (0.5) 59.7 (0.5) 0.745 (0.023) 0.001 (0.001) 0.623 (0.030)
l1-PLS-GL 10.5 (2.3) 27.9 (3.2) 61.6 (5.2) 0.782 (0.070) 0.008 (0.004) 0.468 (0.081)
ACWL 16.8 (1.9) 16.2 (3.5) 67.0 (3.1) 0.793 (0.055) 0.007 (0.002) 0.475 (0.033)
D-learning 9.9 (1.6) 30.0 (1.7) 60.2 (0.7) 0.783 (0.027) 0.006 (0.001) 0.543 (0.039)
b = 5 l1-PLS-HGL 26.4 (0.4) 33.4 (0.5) 40.3 (0.3) 0.410 (0.022) −0.007 (0.001) 0.648 (0.031)
l1-PLS-GL 18.2 (3.2) 48.4 (6.2) 33.4 (3.4) 0.324 (0.059) −0.004 (0.002) 0.485 (0.084)
ACWL 30.1 (2.5) 22.6 (4.2) 47.3 (3.2) 0.422 (0.053) −0.005 (0.002) 0.541 (0.046)
D-learning 19.3 (1.6) 37.4 (1.3) 43.3 (0.7) 0.505 (0.031) −0.004 (0.001) 0.622 (0.045)

Note: Means and standard deviations (in parenthesis) of assignment proportions in % and empirical ITR effects on donation, deferral, and utility across 100 repetitions of 5-fold cross-validation are reported. ITR effects measure the difference in the average outcome between donors whose assigned inter-donation intervals in the trial are optimal (with respect to the method used to estimate the ITR) and those whose assigned inter-donation intervals are non-optimal. A larger ITR effect on donation/utility and a smaller ITR effect on deferral are more desirable.