That is only true for the healthcare costs.Societal costs includes health costs
After rereading parts of the paper and crunching some more numbers, it is clearer now that societal costs includes healthcare. Societal = health costs + lost employment/production + unpaid informal care. I think I made a mistake in a previous post when calculating societal costs vs health costs.
Some of the wording is difficult to interpret at first glance. As far as I can tell, there was a significant advantage for both CBT and GET vs SMC in terms of informal care costs, but not for overall societal costs which includes informal care. However, "Net benefit values were computed for each study participant, defined as the value of a QALY multiplied by the number of QALYs gained minus the cost (from both healthcare and societal perspectives)." So the relative cost-effectiveness of CBT and GET was not achieved by a raw reduction in overall societal costs from Table 3, but rather by subtracting those costs from the estimated value of the gain in QALY.
CBT and GET resulted in reductions in societal cost, but the difference wasn't statistically significant.
What they did was: "If costs for one treatment were lower and outcomes better than another treatment, that treatment was defined as ‘dominant’." That was the case for all the CBT and GET vs SCM calculations involving societal cost calculation. They did then calculation some probabilities.