Cost-effectiveness per 10% increase in online course visits^{b}^{,}^{c} | US$1,770.21 |

Cost-effectiveness per 10% increase in end line knowledge score^{b}^{,}^{d} | US$61,451.77 |

Cost per intervention participant | US$1681.55 |

Cost per control participant | US$58.30 |

↵a All figures are presented in real 2016 U.S. dollars.

↵b For the intervention group, the cost was the full cost of the preparation period and 90% of the intervention costs (US$89,122.30). For the control group, the costs consisted of 10% of the implementation costs (i.e., cost of the text messages once a week and a small amount of the cost to maintain the server and SMS system, US$3089.82).

↵c Clinicians in the intervention group visited the online courses 134 times, and clinicians in the control group visited the online courses 27 times. Overall, the difference in online course visits between the intervention and control group was 107. The following equation was used to determine cost-effectiveness: ICEA = (CI−CC)/(MI−MC), where ICEA is the incremental cost-effectiveness ratio; CI and CC are the total (discounted) costs related to the intervention and control groups, respectively; and MI−MC are the (discounted) change in online course visits. Given that we wanted to calculate the percentage increase, the percentage increase from 27 visits to 134 is 486%. Therefore, the equation was as follows (US$89,122.30–US$3089.82)/(486%)=177.02 for a 1% increase or *10 = US$1770.21 for a 10% increase.

↵d The average change in score for the intervention group was +26% between baseline and endline. The average change in score for the control group was +12%. The following equation was used to determine cost-effectiveness: ICEA = (CI−CC)/(MI−MC), where ICEA is the incremental cost-effectiveness ratio; CI and CC are the total (discounted) costs related to the intervention and control groups, respectively; and MI−MC are the (discounted) change in exam scores. Therefore, the equation was as follows (US$89,122.30–US$3089.82)/(26%–12%) = US$6,145.12 for a 1% increase or *10=US$61,451.77 for a 10% increase in knowledge for the full study population (N=53).